dm vdo volume-index: fix an assert statement in start_restoring_volume_sub_index()

Use "==" instead of "=" in ASSERT() statement.

Fixes: ef074a31e88e ("dm vdo: implement the volume index")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Susan LeGendre-McGhee <slegendr@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm-vdo/volume-index.c

@@ -834,7 +834,7 @@ static int start_restoring_volume_sub_index(struct volume_sub_index *sub_index,
 		decode_u32_le(buffer, &offset, &header.first_list);
 		decode_u32_le(buffer, &offset, &header.list_count);
 
-		result = ASSERT(offset = sizeof(buffer),
+		result = ASSERT(offset == sizeof(buffer),
 				"%zu bytes decoded of %zu expected", offset,
 				sizeof(buffer));
 		if (result != UDS_SUCCESS)