qcacmn: Fix qdf_snprintf() wrapper

Current Linux version of qdf_snprintf() doesn't pass the additional
arguments(...) to snprintf(). As a result, the behavior is undefined.
Fix it by passing the additional arguments as a variable-argument-list to
vsnprintf().

Change-Id: Iea8ee0737907eaaea2df99631316d7d45a8e562f
CRs-Fixed: 2838962

qdf/linux/src/qdf_trace.c

@@ -114,7 +114,11 @@ static tp_qdf_dp_trace_cb qdf_dp_trace_cb_table[QDF_DP_TRACE_MAX + 1];
  */
 void qdf_snprintf(char *str_buffer, unsigned int size, char *str_format, ...)
 {
-	snprintf(str_buffer, size, str_format);
+	va_list args;
+
+	va_start(args, str_format);
+	vsnprintf(str_buffer, size, str_format, args);
+	va_end(args);
 }
 qdf_export_symbol(qdf_snprintf);