switch cpu flags to 0 for unitialized to avoid compare

source/cpu_id.cc

Index: source/cpu_id.cc
diff --git a/source/cpu_id.cc b/source/cpu_id.cc
index 381d40f161b51287f78778fd8353f15b4eabd2e3..9465df6562c92466cda77ee84db2228ac8892175 100644
--- a/source/cpu_id.cc
+++ b/source/cpu_id.cc
@@ -174,7 +174,7 @@ static int MipsCpuCaps(const char* search_string) {
 
 // CPU detect function for SIMD instruction sets.
 LIBYUV_API
-int cpu_info_ = kCpuInit;  // cpu_info is not initialized yet.
+int cpu_info_ = 0;  // cpu_info is not initialized yet.
 
 // Test environment variable for disabling CPU features. Any non-zero value
 // to disable. Zero ignored to make it easy to set the variable on/off.
@@ -291,8 +291,9 @@ int InitCpuFlags(void) {
   if (TestEnv("LIBYUV_DISABLE_ASM")) {
     cpu_info = 0;
   }
+  cpu_info  |= kCpuInitialized;
   cpu_info_ = cpu_info;
-  return cpu_info_;
+  return cpu_info;
 }
 
 // Note that use of this function is not thread safe.