[4/5 PATCH/RFC PPC64] add power8 keyword for clang/tools

Add power8/pwr8 to clang/tools

diff --git a/tools/clang/lib/Driver/Tools.cpp
b/tools/clang/lib/Driver/Tools.cpp
index de03ce6..d353069 100644
--- a/tools/clang/lib/Driver/Tools.cpp
+++ b/tools/clang/lib/Driver/Tools.cpp
@@ -1156,6 +1156,7 @@ static std::string getPPCTargetCPU(const ArgList
&Args) {
       .Case("power6", "pwr6")
       .Case("power6x", "pwr6x")
       .Case("power7", "pwr7")
+ .Case("power8", "pwr8")
       .Case("pwr3", "pwr3")
       .Case("pwr4", "pwr4")
       .Case("pwr5", "pwr5")
@@ -1163,6 +1164,7 @@ static std::string getPPCTargetCPU(const ArgList
&Args) {
       .Case("pwr6", "pwr6")
       .Case("pwr6x", "pwr6x")
       .Case("pwr7", "pwr7")
+ .Case("pwr8", "pwr8")
       .Case("powerpc", "ppc")
       .Case("powerpc64", "ppc64")
       .Case("powerpc64le", "ppc64le")