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.c b/cache-utils.c
index 7df1fcf..b37ddd4 100644
--- a/cache-utils.c
+++ b/cache-utils.c
@@ -1,6 +1,6 @@
 #include "cache-utils.h"
 
-#if defined HOST_PPC || defined HOST_PPC64
+#if defined(_ARCH_PPC)
 struct qemu_cache_conf qemu_cache_conf = {
     .dcache_bsize = 16,
     .icache_bsize = 16
@@ -68,4 +68,4 @@
 }
 #endif
 
-#endif /* HOST_PPC || HOST_PPC64  */
+#endif /* _ARCH_PPC */