Allow custom time functions on STM32

Author: lealem47

wolfssl/wolfcrypt/settings.h

@@ -2283,7 +2283,7 @@ extern void uITRON4_free(void *p) ;
             #define STM32_HAL_TIMEOUT   0xFF
         #endif
         /* bypass certificate date checking, due to lack of properly configured RTC source */
-        #ifndef HAL_RTC_MODULE_ENABLED
+        #if !defined(HAL_RTC_MODULE_ENABLED) && !defined(XTIME)
             #define NO_ASN_TIME
         #endif