[Yaffs] about yaffs_skip_rest_of_block

Hi,everyone
Now I skip over the rest of the allocation block in the end of function yaffs_scan_backwarks, so there is no summary in this block.
It will cost extra time when we remount the yaffs filesystem if this block hasn't been already erased.
Now we want to set gc_prioritise flag to 1 when skip over the block, so that the gc thread can erase the block quickly.
Does this modification reasonalbe and effective on this situation?