fpga: dfl: Add lockdep classes for pdata->lock

struct dfl_feature_platform_data (and it's mutex) is used
by both fme and port devices, and when lockdep is enabled it
complains about nesting between these locks.  Tell lockdep about
the difference so it can track each class separately.

Here's the lockdep complaint:
[  409.680668] WARNING: possible recursive locking detected
[  409.685983] 5.1.0-rc3.fpga+ #1 Tainted: G            E
[  409.691469] --------------------------------------------
[  409.696779] fpgaconf/9348 is trying to acquire lock:
[  409.701746] 00000000a443fe2e (&pdata->lock){+.+.}, at: port_enable_set+0x24/0x60 [dfl_afu]
[  409.710006]
[  409.710006] but task is already holding lock:
[  409.715837] 0000000063b78782 (&pdata->lock){+.+.}, at: fme_pr_ioctl+0x21d/0x330 [dfl_fme]
[  409.724012]
[  409.724012] other info that might help us debug this:
[  409.730535]  Possible unsafe locking scenario:
[  409.730535]
[  409.736457]        CPU0
[  409.738910]        ----
[  409.741360]   lock(&pdata->lock);
[  409.744679]   lock(&pdata->lock);
[  409.747999]
[  409.747999]  *** DEADLOCK ***
[  409.747999]
[  409.753920]  May be due to missing lock nesting notation
[  409.753920]
[  409.760704] 4 locks held by fpgaconf/9348:
[  409.764805]  #0: 0000000063b78782 (&pdata->lock){+.+.}, at: fme_pr_ioctl+0x21d/0x330 [dfl_fme]
[  409.773408]  #1: 00000000213c8a66 (&region->mutex){+.+.}, at: fpga_region_program_fpga+0x24/0x200 [fpga_region]
[  409.783489]  #2: 00000000fe63afb9 (&mgr->ref_mutex){+.+.}, at: fpga_mgr_lock+0x15/0x40 [fpga_mgr]
[  409.792354]  #3: 000000000b2285c5 (&bridge->mutex){+.+.}, at: __fpga_bridge_get+0x26/0xa0 [fpga_bridge]
[  409.801740]
[  409.801740] stack backtrace:
[  409.806102] CPU: 45 PID: 9348 Comm: fpgaconf Kdump: loaded Tainted: G            E     5.1.0-rc3.fpga+ #1
[  409.815658] Hardware name: Intel Corporation S2600BT/S2600BT, BIOS SE5C620.86B.01.00.0763.022420181017 02/24/2018
[  409.825911] Call Trace:
[  409.828369]  dump_stack+0x5e/0x8b
[  409.831686]  __lock_acquire+0xf3d/0x10e0
[  409.835612]  ? find_held_lock+0x3c/0xa0
[  409.839451]  lock_acquire+0xbc/0x1d0
[  409.843030]  ? port_enable_set+0x24/0x60 [dfl_afu]
[  409.847823]  ? port_enable_set+0x24/0x60 [dfl_afu]
[  409.852616]  __mutex_lock+0x86/0x970
[  409.856195]  ? port_enable_set+0x24/0x60 [dfl_afu]
[  409.860989]  ? port_enable_set+0x24/0x60 [dfl_afu]
[  409.865777]  ? __mutex_unlock_slowpath+0x4b/0x290
[  409.870486]  port_enable_set+0x24/0x60 [dfl_afu]
[  409.875106]  fpga_bridges_disable+0x36/0x50 [fpga_bridge]
[  409.880502]  fpga_region_program_fpga+0xea/0x200 [fpga_region]
[  409.886338]  fme_pr_ioctl+0x13e/0x330 [dfl_fme]
[  409.890870]  fme_ioctl+0x66/0xe0 [dfl_fme]
[  409.894973]  do_vfs_ioctl+0xa9/0x720
[  409.898548]  ? lockdep_hardirqs_on+0xf0/0x1a0
[  409.902907]  ksys_ioctl+0x60/0x90
[  409.906225]  __x64_sys_ioctl+0x16/0x20
[  409.909981]  do_syscall_64+0x5a/0x220
[  409.913644]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  409.918698] RIP: 0033:0x7f9d31b9b8d7
[  409.922276] Code: 44 00 00 48 8b 05 b9 15 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 89 15 2d 00 f7 d8 64 89 01 48
[  409.941020] RSP: 002b:00007ffe4cae0d68 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[  409.948588] RAX: ffffffffffffffda RBX: 00007f9d32ade6a0 RCX: 00007f9d31b9b8d7
[  409.955719] RDX: 00007ffe4cae0df0 RSI: 000000000000b680 RDI: 0000000000000003
[  409.962852] RBP: 0000000000000003 R08: 00007f9d2b70a177 R09: 00007ffe4cae0e40
[  409.969984] R10: 00007ffe4cae0160 R11: 0000000000000202 R12: 00007ffe4cae0df0
[  409.977115] R13: 000000000000b680 R14: 0000000000000000 R15: 00007ffe4cae0f60

Signed-off-by: Scott Wood <swood@redhat.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>