blk_dwrite/blk_derase returns the number of blocks
written/erased. The existing check allowed partial
writes or partial erase to be considered successful.
Fix error handling of blk_dwrite/blk_derase by checking
that return value corresponds to the number of blocks
written/erased.
Signed-off-by: Francois Berder <fberder@outlook.fr>
4feabb2b8a