Coverity 1506566: unchecked return value

There isn't much else that can be done here unfortunately.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18799)

crypto/bio/bss_dgram.c

@@ -1914,7 +1914,8 @@ static void get_current_time(struct timeval *t)
     t->tv_sec = (long)(now_ul / 10000000);
     t->tv_usec = ((int)(now_ul % 10000000)) / 10;
 # else
-    gettimeofday(t, NULL);
+    if (gettimeofday(t, NULL) < 0)
+        perror("gettimeofday");
 # endif
 }