[PowerPC] Remove unnecessary preprocessor checking.

The tests !defined(__ppc__) && !defined(__powerpc__) are not needed
or helpful when verifying that code is being compiled for a 64-bit
target.  The simpler test provided by this revision is sufficient to
tell if the target is 64-bit.

llvm-svn: 187318
diff --git a/llvm/lib/Target/PowerPC/PPCJITInfo.cpp b/llvm/lib/Target/PowerPC/PPCJITInfo.cpp
index 18f4adf..01ddcbe 100644
--- a/llvm/lib/Target/PowerPC/PPCJITInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCJITInfo.cpp
@@ -71,7 +71,7 @@
 extern "C" void PPC32CompilationCallback();
 extern "C" void PPC64CompilationCallback();
 
-#if (!defined(__ppc__) && !defined(__powerpc__)) || defined(__powerpc64__) || defined(__ppc64__)
+#if defined(__powerpc64__) || defined(__ppc64__)
 void PPC32CompilationCallback() {
   llvm_unreachable("This is not a 32bit PowerPC, you can't execute this!");
 }