block: remove obsolete config BLOCK_COMPAT

Before commit bdc1ddad ("compat_ioctl: block: move
blkdev_compat_ioctl() into ioctl.c"), the config BLOCK_COMPAT was used to
include compat_ioctl.c into the kernel build. With this commit, the code
is moved into ioctl.c and included with the config COMPAT. So, since then,
the config BLOCK_COMPAT has no effect and any further purpose.

Remove this obsolete config BLOCK_COMPAT.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230316111630.4897-1-lukas.bulwahn@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/Kconfig

@@ -204,9 +204,6 @@ config BLK_INLINE_ENCRYPTION_FALLBACK
 
 source "block/partitions/Kconfig"
 
-config BLOCK_COMPAT
-	def_bool COMPAT
-
 config BLK_MQ_PCI
 	def_bool PCI