Makefile: apply xtensa specific TARGET_SKELETON_PATCH if available

Part of #163.

Signed-off-by: Maxim Grigoriev <maxim2405@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

Makefile

@@ -332,6 +332,9 @@ $(PROJECT_BUILD_DIR)/.root:
 		if [ -d "$(TARGET_SKELETON)" ]; then \
 			cp -fa $(TARGET_SKELETON)/* $(TARGET_DIR)/; \
 		fi; \
+		if [ -d "$(TARGET_SKELETON_PATCH)" ]; then \
+			toolchain/patch-kernel.sh $(TARGET_DIR) $(TARGET_SKELETON_PATCH)/ \*patch\*; \
+		fi; \
 		touch $(STAGING_DIR)/.fakeroot.00000; \
 	fi
 	-find $(TARGET_DIR) -type d -name CVS -o -name .svn -print0 | xargs -0 rm -rf