remove IPKG_ARCH variable, unused anymore since ipkg support was removed from busybox

SVN-Revision: 14142

package/busybox/Makefile

@@ -1,5 +1,5 @@
 # 
-# Copyright (C) 2006-2008 OpenWrt.org
+# Copyright (C) 2006-2009 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -67,7 +67,6 @@ define Build/Compile
 		KBUILD_HAVE_NLS=no \
 		EXTRA_CFLAGS="$(TARGET_CFLAGS)" \
 		ARCH="$(ARCH)" \
-		IPKG_ARCH="$(ARCH)" \
 		all
 endef