Fix AVR32 gcc patching, when sysroot option is not enabled

toolchain/gcc/gcc-uclibc-3.x.mk

@@ -36,7 +36,7 @@ endif
 ifneq ($(BR2_TOOLCHAIN_BUILDROOT),y)
 GCC_SITE:=$(VENDOR_SITE)
 GCC_OFFICIAL_VER:=$(GCC_VERSION)$(VENDOR_SUFFIX)$(VENDOR_GCC_RELEASE)
-GCC_PATCH_DIR:=$(VENDOR_PATCH_DIR)/gcc-$(GCC_OFFICIAL_VER)
+GCC_PATCH_DIR:=toolchain/gcc/ext_source/$(VENDOR_PATCH_DIR)/$(GCC_OFFICIAL_VERSION)
 endif
 
 GCC_SOURCE:=gcc-$(GCC_OFFICIAL_VER).tar.bz2