libobs: Remove dependency on Visual Studio 2019+

In util_uint64.h the intrinsic function _udiv128 is used.
The implementation is only available in Visual Studio 2019+

libobs/util/util_uint64.h

@@ -22,7 +22,7 @@
 
 static inline uint64_t util_mul_div64(uint64_t num, uint64_t mul, uint64_t div)
 {
-#if defined(_MSC_VER) && defined(_M_X64)
+#if defined(_MSC_VER) && defined(_M_X64) && (_MSC_VER >= 1920)
 	unsigned __int64 high;
 	const unsigned __int64 low = _umul128(num, mul, &high);
 	unsigned __int64 rem;