clk: Fix memory leak in clk_unregister()

Memory allocated in alloc_clk() for 'struct clk' and
'const char *con_id' while invoking clk_register() is never freed
in clk_unregister(), resulting in kmemleak showing the following
backtrace.

  backtrace:
    [<00000000546f5dd0>] kmem_cache_alloc+0x18c/0x270
    [<0000000073a32862>] alloc_clk+0x30/0x70
    [<0000000082942480>] __clk_register+0xc8/0x760
    [<000000005c859fca>] devm_clk_register+0x54/0xb0
    [<00000000868834a8>] 0xffff800008c60950
    [<00000000d5a80534>] platform_drv_probe+0x50/0xa0
    [<000000001b3889fc>] really_probe+0x108/0x348
    [<00000000953fa60a>] driver_probe_device+0x58/0x100
    [<0000000008acc17c>] device_driver_attach+0x6c/0x90
    [<0000000022813df3>] __driver_attach+0x84/0xc8
    [<00000000448d5443>] bus_for_each_dev+0x74/0xc8
    [<00000000294aa93f>] driver_attach+0x20/0x28
    [<00000000e5e52626>] bus_add_driver+0x148/0x1f0
    [<000000001de21efc>] driver_register+0x60/0x110
    [<00000000af07c068>] __platform_driver_register+0x40/0x48
    [<0000000060fa80ee>] 0xffff800008c66020

Fix it here.

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Link: https://lkml.kernel.org/r/20191022071153.21118-1-kishon@ti.com
Fixes: 1df4046a

 ("clk: Combine __clk_get() and __clk_create_clk()")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>