exfat: Simplify exfat_utf8_d_cmp() for code points above U+FFFF

If two Unicode code points represented in UTF-16 are different then also
their UTF-32 representation must be different. Therefore conversion from
UTF-32 to UTF-16 is not needed.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

fs/exfat/namei.c

@@ -185,14 +185,9 @@ static int exfat_utf8_d_cmp(const struct dentry *dentry, unsigned int len,
 		if (u_a <= 0xFFFF && u_b <= 0xFFFF) {
 			if (exfat_toupper(sb, u_a) != exfat_toupper(sb, u_b))
 				return 1;
-		} else if (u_a > 0xFFFF && u_b > 0xFFFF) {
-			if (exfat_low_surrogate(u_a) !=
-					exfat_low_surrogate(u_b) ||
-			    exfat_high_surrogate(u_a) !=
-					exfat_high_surrogate(u_b))
-				return 1;
 		} else {
-			return 1;
+			if (u_a != u_b)
+				return 1;
 		}
 	}