libobs: fix windows version log warning

OSVERSIONINFOW uses SIZE_T so cast to unsigned long instead.

libobs/obs-windows.c

@@ -178,9 +178,9 @@ static void log_available_memory(void)
 	const char *note = " (NOTE: 4 gigs max is normal for 32bit programs)";
 #endif
 
-	blog(LOG_INFO, "Physical Memory: %ldMB Total, %ldMB Free%s",
-			ms.dwTotalPhys / 1048576,
-			ms.dwAvailPhys / 1048576,
+	blog(LOG_INFO, "Physical Memory: %luMB Total, %luMB Free%s",
+			(DWORD)(ms.dwTotalPhys / 1048576),
+			(DWORD)(ms.dwAvailPhys / 1048576),
 			note);
 }