Move platform specific clean rules into platform specific files

The generic code was expecting the marvell platform support to be in the
same directory. Clean this up.
Signed-off-by: Grant Likely <grant.likely@arm.com>

config-mvebu_armada-8k.mk

@@ -17,6 +17,13 @@ ifeq ($(CONFIG_DEFAULT_DEVICE_TREE),"armada-8040-mcbin")
 TFA_PLAT := a80x0_mcbin
 endif
 
+mv-ddr-clean:
+	cd $(CURDIR)/mv-ddr && git clean -fdx
+
+clean: mv-ddr-clean
+mrproper: mv-ddr-clean
+distclean: mv-ddr-clean
+
 sdimage: $(FLASH_IMAGE)
 	dd if=/dev/zero of=$(SD_IMAGE) count=$$((128*1024*1024>>9))
 	echo "label: dos\n$$(($(ESP_OFFSET)>>9)) - 0xef -" | /sbin/sfdisk $(SD_IMAGE)

top.mk

@@ -275,13 +275,8 @@ sdimage: flashimage
 
 PHONY += clean mrproper distclean
 clean: u-boot/clean tfa/distclean devicetree/clean optee_os/clean
-	cd $(CURDIR)/mv-ddr && git clean -fdx
-
-mrproper: u-boot/mrproper tfa/distclean devicetree/clean
-	cd $(CURDIR)/mv-ddr && git clean -fdx
-
-distclean: u-boot/distclean tfa/distclean devicetree/clean
-	cd $(CURDIR)/mv-ddr && git clean -fdx
+mrproper: u-boot/mrproper tfa/distclean devicetree/clean optee_os/clean
+distclean: u-boot/distclean tfa/distclean devicetree/clean optee_os/clean
 
 endif #ifeq ($(config-targets),1)