[OpenMP] Fix the usage of sscanf on MinGW

KMP_SSCANF only evaluates to sscanf_s within
    #if KMP_OS_WINDOWS && KMP_MSVC_COMPAT
so we need to pass the sscanf_s specific parameters within a similar
condition.

Differential Revision: https://reviews.llvm.org/D108196

openmp/runtime/src/kmp_settings.cpp

@@ -164,7 +164,7 @@ int __kmp_convert_to_milliseconds(char const *data) {
     return (INT_MAX);
   value = (double)0.0;
   mult = '\0';
-#if KMP_OS_WINDOWS
+#if KMP_OS_WINDOWS && KMP_MSVC_COMPAT
   // On Windows, each %c parameter needs additional size parameter for sscanf_s
   nvalues = KMP_SSCANF(data, "%lf%c%c", &value, &mult, 1, &extra, 1);
 #else