zram: remove valid_io_request

zram: remove valid_io_request

All bios hande to drivers from the block layer are checked against the
device size and for logical block alignment already (and have been since
long before zram was merged), so don't duplicate those checks.

Link: https://lkml.kernel.org/r/20230411171459.567614-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>