Add an assembly __kmp_invoke_microtask for ppc64[le]

Clang no longer restricts itself to generating microtasks with a small number
of arguments, and so an assembly implementation is required to prevent hitting
the parameter limit present in the C implementation. This adds an
implementation for ppc64[le].

llvm-svn: 270821
diff --git a/openmp/runtime/src/z_Linux_util.c b/openmp/runtime/src/z_Linux_util.c
index 126509d..4543c55 100644
--- a/openmp/runtime/src/z_Linux_util.c
+++ b/openmp/runtime/src/z_Linux_util.c
@@ -2575,7 +2575,7 @@
 
 #endif // USE_LOAD_BALANCE
 
-#if !(KMP_ARCH_X86 || KMP_ARCH_X86_64 || KMP_MIC || (KMP_OS_LINUX && KMP_ARCH_AARCH64))
+#if !(KMP_ARCH_X86 || KMP_ARCH_X86_64 || KMP_MIC || (KMP_OS_LINUX && KMP_ARCH_AARCH64) || KMP_ARCH_PPC64)
 
 // we really only need the case with 1 argument, because CLANG always build
 // a struct of pointers to shared variables referenced in the outlined function