ramips: clean UBI tempdir before image creation

Clean the temporary directory the UBI image is generated from before
generation.

Currently it is removed after the image generation, which leads to files
possibly not being cleared after a build failure in this step.

Signed-off-by: David Bauer <[email protected]>

target/linux/ramips/image/mt7621.mk

@@ -92,6 +92,7 @@ define Build/inteno-y3-header
 endef
 
 define Build/inteno-bootfs
+	rm -rf [email protected]
 	mkdir -p [email protected]/boot
 
 	# populate the boot fs with the dtb and the kernel image
@@ -100,7 +101,6 @@ define Build/inteno-bootfs
 
 	# create ubifs
 	$(STAGING_DIR_HOST)/bin/mkfs.ubifs ${MKUBIFS_OPTS} -r [email protected]/ -o [email protected]
-	rm -rf [email protected]
 	mv [email protected] $@
 endef