Change sprintf to snprint in uniden.c

https://github.com/Hamlib/Hamlib/issues/857

rigs/uniden/uniden.c

@@ -278,15 +278,14 @@ transaction_quit:
 int uniden_set_freq(RIG *rig, vfo_t vfo, freq_t freq)
 {
     char freqbuf[BUFSZ];
-    size_t freq_len = BUFSZ;
 
     /* freq in hundreds of Hz */
     freq /= 100;
 
     /* exactly 8 digits */
-    freq_len = sprintf(freqbuf, "RF%08u" EOM, (unsigned)freq);
+    SNPRINTF(freqbuf, sizeof(freqbuf), "RF%08u" EOM, (unsigned)freq);
 
-    return uniden_transaction(rig, freqbuf, freq_len, NULL, NULL, NULL);
+    return uniden_transaction(rig, freqbuf, strlen(freqbuf), NULL, NULL, NULL);
 }
 
 /*