Makefile: Fix the clean target by re-ordering

The sstate cleaning requires a tmp directory. So don't delete it first.

Makefile

@@ -129,8 +129,8 @@ build.%: | git/poky
 	$(Q)cd build.$(CUR_MACHINE) && ../scripts/upload-build.sh $(CUR_MACHINE) $(FEED_NAME)
 
 %-clean: | build.$(subst -clean,,%) git/poky
-	$(Q)cd build.$(CUR_MACHINE) && rm -rf tmp
 	$(Q)cd build.$(CUR_MACHINE) && ../git/poky/scripts/sstate-cache-management.sh  --cache-dir=sstate-cache -y -L --stamps-dir=tmp/stamps/
+	$(Q)cd build.$(CUR_MACHINE) && rm -rf tmp
 
 # Create all build directories, build everything, upload everything, clean everything
 setup-all: | $(foreach machine, $(MACHINES), $(machine)-setup)