Revert "[MTD] blkdev helper code: fix printk format warning"

This reverts commit 668040fc.

The 'flags' field of the struct request is 'unsigned long'. Quite
how Randy came to see 'long int format, different type arg' I don't
know, but it doesn't seem to be the case any more.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>