Move creation of $(PROJECT_BUILD_DIR)/autotools-stamps into top level Makefile

This patch will create the autotools-stamps directory early in the build
process, thus making it possible for non Makefile.autotools.in packages to use
this directory to hold stamp files.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>

Makefile

@@ -318,6 +318,7 @@ endif
 
 $(PROJECT_BUILD_DIR)/.root:
 	mkdir -p $(TARGET_DIR)
+	mkdir -p $(PROJECT_BUILD_DIR)/autotools-stamps
 	if ! [ -d "$(TARGET_DIR)/bin" ]; then \
 		if [ -d "$(TARGET_SKELETON)" ]; then \
 			cp -fa $(TARGET_SKELETON)/* $(TARGET_DIR)/; \

package/Makefile.autotools.in

@@ -258,7 +258,6 @@ $(PROJECT_BUILD_DIR)/autotools-stamps/%_target_installed:
 	$(if $(BR2_HAVE_DOCUMENTATION),,for d in doc share/doc; do \
 		rm -rf $(TARGET_DIR)/$$d $(TARGET_DIR)/usr/$$d; \
 	done)
-	$(Q)mkdir -p $(@D)
 	touch $@
 
 $(BUILD_DIR)/%/.stamp_cleaned: