[PPC] Modify HTM and crypto intrinsics to inherit from GCCBuiltin

There was a change to the way some of the HTM and crypto builtins are being
handled in Clang. Previously, some of the builtins were dealt with in the
CodeGenFunction::EmitPPCBuiltinExpr method (in order to do range checking on
constant arguments). These check will been moved to Sema
http://reviews.llvm.org/D8672), which means those builtins will not be handled
in the EmitPPCBuiltinExpr method anymore. As a result, the definition of the
intrinsics in IntrinsicsPowerPC.td needs to be modified to inherit from the
GCCBuiltin definition.

http://reviews.llvm.org/D8673

llvm-svn: 233581