mtd: mtdram: check offs and len in mtdram->erase
mtd: mtdram: check offs and len in mtdram->erase

We should prevent user to erasing mtd device with
an unaligned offset or length.

Signed-off-by: Dongsheng Yang <1b957dfff8d0f16ed124fab3c79d8c1232c34692@cn.fujitsu.com>
Signed-off-by: Brian Norris <ac73eed4b8a8c9127255a2696c52b2e7503720b8@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs