fsck.f2fs: fix to use strncmp to avoid out-of-boundary access

Otherwise, if length of main device path is equal to MAX_PATH_LEN,
it will trigger assert() as below:

[ASSERT] (init_sb_info:1264) !strcmp((char *)sb->devs[i].path, (char *)c.devices[i].path)

This is because there is no null character in the end of devcie
path string, result in out-of-boundary access in devs.path[].

Let's use strncmp instead of strcmp to compare device path to fix
this issue.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: chaseyu

fsck/mount.c

@@ -1261,8 +1261,9 @@ int init_sb_info(struct f2fs_sb_info *sbi)
 			if (get_device_info(i))
 				ASSERT(0);
 		} else if (c.func != INJECT) {
-			if (strcmp((char *)sb->devs[i].path,
-					(char *)c.devices[i].path)) {
+			if (strncmp((char *)sb->devs[i].path,
+					(char *)c.devices[i].path,
+					MAX_PATH_LEN)) {
 				MSG(0, "paths mismatch: %s, %s\n",
 					(char *)sb->devs[i].path,
 					(char *)c.devices[i].path);