Remove all traces of __powerpc__

According to $GCC/gcc/config/rs6000/rs6000-c.c _ARCH_PPC is the
ubiquitous define which should be used to test whether gcc targets
PowerPC, on 64bit platforms _ARCH_PPC64 will be also defined.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6301 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/cache-utils.h b/cache-utils.h
index 8847dbb..b45fde4 100644
--- a/cache-utils.h
+++ b/cache-utils.h
@@ -1,9 +1,7 @@
 #ifndef QEMU_CACHE_UTILS_H
 #define QEMU_CACHE_UTILS_H
 
-#include "config-host.h"
-
-#if defined HOST_PPC || defined HOST_PPC64
+#if defined(_ARCH_PPC)
 struct qemu_cache_conf {
     unsigned long dcache_bsize;
     unsigned long icache_bsize;