Clean up duplicate includes in drivers/block/

This patch cleans up duplicate includes in
	drivers/block/

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Satyam Sharma <satyam.sharma@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>