clangcl build fix for __cpuid in psnr util. Since clangcl provides the intrinsic…

clangcl build fix for __cpuid in psnr util. Since clangcl provides the intrinsic thru its Visual C emulation, don't duplicately define the function with an inline version, which is normally needed for gcc/clang.
BUG=412
TESTED=set GYP_DEFINES=clang=1 & gyp_libyuv -fninja libyuv_test.gyp
R=brucedawson@google.com

Review URL: https://webrtc-codereview.appspot.com/40339004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1331 16f28f9a-4ce2-e073-06de-1de4eb20be90

util/psnr.cc

@@ -206,7 +206,8 @@ static __inline void __cpuid(int cpu_info[4], int info_type) {
     : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
     : "a"(info_type));
 }
-#elif defined(__i386__) || defined(__x86_64__)
+// For gcc/clang but not clangcl.
+#elif (defined(__i386__) || defined(__x86_64__)) && !defined(_MSC_VER)
 static __inline void __cpuid(int cpu_info[4], int info_type) {
   asm volatile (  // NOLINT
     "cpuid                                     \n"