[X86] Add RDPRU instruction CPUID bit masks

As mentioned on D128934 - we weren't including the CPUID bit handling for the RDPRU instruction

AMD's APMv3 (24594) lists it as CPUID Fn8000_0008_EBX Bit#4

(cherry picked from commit 08a8805)

Author: RKSimon

clang/lib/Headers/cpuid.h

@@ -232,6 +232,7 @@
 
 /* Features in %ebx for leaf 0x80000008 */
 #define bit_CLZERO      0x00000001
+#define bit_RDPRU       0x00000010
 #define bit_WBNOINVD    0x00000200
 
 

llvm/lib/Support/Host.cpp

@@ -1734,6 +1734,7 @@ bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
   bool HasExtLeaf8 = MaxExtLevel >= 0x80000008 &&
                      !getX86CpuIDAndInfo(0x80000008, &EAX, &EBX, &ECX, &EDX);
   Features["clzero"]   = HasExtLeaf8 && ((EBX >> 0) & 1);
+  Features["rdpru"]    = HasExtLeaf8 && ((EBX >> 4) & 1);
   Features["wbnoinvd"] = HasExtLeaf8 && ((EBX >> 9) & 1);
 
   bool HasLeaf7 =