Revert "cmake: add explicit MSVC /volatile:ms (required for arm) (#451)"

This reverts commit 1e397ae.

Reason for revert: This is no longer needed as we are using intrinsics
for atomics now.

CMakeLists.txt

@@ -49,7 +49,7 @@ set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_EXTENSIONS OFF)
 
 if(MSVC)
-  add_compile_options("/W3" "/volatile:ms")
+  add_compile_options("/W3")
 else()
   add_compile_options(
     -Wall