f2fs: fix dcache lookup of !casefolded directories

Do the name comparison for non-casefolded directories correctly.

This is analogous to ext4's commit 66883da1 ("ext4: fix dcache
lookup of !casefolded directories").

Fixes: 2c2eb7a3 ("f2fs: Support case-insensitive file name lookups")
Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/dir.c

@@ -1087,7 +1087,7 @@ static int f2fs_d_compare(const struct dentry *dentry, unsigned int len,
 	if (!IS_CASEFOLDED(dentry->d_parent->d_inode)) {
 		if (len != name->len)
 			return -1;
-		return memcmp(str, name, len);
+		return memcmp(str, name->name, len);
 	}
 
 	return f2fs_ci_compare(dentry->d_parent->d_inode, name, &qstr, false);