lib: hex: remove unnecessary defensive programming

The hex2char() calls in bin2hex() can never fail since buf[i] >> 4
and buf[i] & 0xf always produce values in range 0-15.

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

Author: kartben

lib/utils/hex.c

@@ -44,12 +44,8 @@ size_t bin2hex(const uint8_t *buf, size_t buflen, char *hex, size_t hexlen)
 	}
 
 	for (size_t i = 0; i < buflen; i++) {
-		if (hex2char(buf[i] >> 4, &hex[2U * i]) < 0) {
-			return 0;
-		}
-		if (hex2char(buf[i] & 0xf, &hex[2U * i + 1U]) < 0) {
-			return 0;
-		}
+		hex2char(buf[i] >> 4, &hex[2U * i]);
+		hex2char(buf[i] & 0xf, &hex[2U * i + 1U]);
 	}
 
 	hex[2U * buflen] = '\0';