pktcdvd: remove warning on attempting to register non-passthrough dev

Anatoly reports that he gets the below warning when booting -git on
a sparc64 box on debian unstable:

...
[   13.352975] aes_sparc64: Using sparc64 aes opcodes optimized AES
implementation
[   13.428002] ------------[ cut here ]------------
[   13.428081] WARNING: CPU: 21 PID: 586 at
drivers/block/pktcdvd.c:2597 pkt_setup_dev+0x2e4/0x5a0 [pktcdvd]
[   13.428147] Attempt to register a non-SCSI queue
[   13.428184] Modules linked in: pktcdvd libdes cdrom aes_sparc64
n2_rng md5_sparc64 sha512_sparc64 rng_core sha256_sparc64 flash
sha1_sparc64 ip_tables x_tables ipv6 crc_ccitt nf_defrag_ipv6 autofs4
ext4 crc16 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy
async_pq async_xor xor async_tx raid6_pq raid1 raid0 multipath linear
md_mod crc32c_sparc64
[   13.428452] CPU: 21 PID: 586 Comm: pktsetup Not tainted
5.3.0-10169-g574cc4539762 #1234
[   13.428507] Call Trace:
[   13.428542]  [00000000004635c0] __warn+0xc0/0x100
[   13.428582]  [0000000000463634] warn_slowpath_fmt+0x34/0x60
[   13.428626]  [000000001045b244] pkt_setup_dev+0x2e4/0x5a0 [pktcdvd]
[   13.428674]  [000000001045ccf4] pkt_ctl_ioctl+0x94/0x220 [pktcdvd]
[   13.428724]  [00000000006b95c8] do_vfs_ioctl+0x628/0x6e0
[   13.428764]  [00000000006b96c8] ksys_ioctl+0x48/0x80
[   13.428803]  [00000000006b9714] sys_ioctl+0x14/0x40
[   13.428847]  [0000000000406294] linux_sparc_syscall+0x34/0x44
[   13.428890] irq event stamp: 4181
[   13.428924] hardirqs last  enabled at (4189): [<00000000004e0a74>]
console_unlock+0x634/0x6c0
[   13.428984] hardirqs last disabled at (4196): [<00000000004e0540>]
console_unlock+0x100/0x6c0
[   13.429048] softirqs last  enabled at (3978): [<0000000000b2e2d8>]
__do_softirq+0x498/0x520
[   13.429110] softirqs last disabled at (3967): [<000000000042cfb4>]
do_softirq_own_stack+0x34/0x60
[   13.429172] ---[ end trace 2220ca468f32967d ]---
[   13.430018] pktcdvd: setup of pktcdvd device failed
[   13.455589] des_sparc64: Using sparc64 des opcodes optimized DES
implementation
[   13.515334] camellia_sparc64: Using sparc64 camellia opcodes
optimized CAMELLIA implementation
[   13.522856] pktcdvd: setup of pktcdvd device failed
[   13.529327] pktcdvd: setup of pktcdvd device failed
[   13.532932] pktcdvd: setup of pktcdvd device failed
[   13.536165] pktcdvd: setup of pktcdvd device failed
[   13.539372] pktcdvd: setup of pktcdvd device failed
[   13.542834] pktcdvd: setup of pktcdvd device failed
[   13.546536] pktcdvd: setup of pktcdvd device failed
[   15.431071] XFS (dm-0): Mounting V5 Filesystem
...

Apparently debian auto-attaches any cdrom like device to pktcdvd, which
can lead to the above warning. There's really no reason to warn for this
situation, kill it.

Reported-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>