fs: block_dev.c: fix kernel-doc warnings from struct block_device changes

Fix new kernel-doc warnings in fs/block_dev.c:

../fs/block_dev.c:1066: warning: Excess function parameter 'whole' description in 'bd_abort_claiming'
../fs/block_dev.c:1837: warning: Function parameter or member 'dev' not described in 'lookup_bdev'

Fixes: 4e7b5671 ("block: remove i_bdev")
Fixes: 37c3fc9a

 ("block: simplify the block device claiming interface")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-fsdevel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>