adb: Improved detection of big endian architecture

Instead of testing for the (compiler specific) define
__ppc__ explicitly, use the define HAVE_BIG_ENDIAN provided by
AndroidConfig.h.  That way, it should work on all big endian
systems.

Change-Id: Ic4d62afcefce4c8ad5716178ebfcb2b055ac73ce
diff --git a/adb/file_sync_service.h b/adb/file_sync_service.h
index 11ea06b..e402e06 100644
--- a/adb/file_sync_service.h
+++ b/adb/file_sync_service.h
@@ -17,7 +17,7 @@
 #ifndef _FILE_SYNC_SERVICE_H_
 #define _FILE_SYNC_SERVICE_H_
 
-#ifdef __ppc__
+#ifdef HAVE_BIG_ENDIAN
 static inline unsigned __swap_uint32(unsigned x) 
 {
     return (((x) & 0xFF000000) >> 24)