ARC: AXS10x/HSDK: Use our own version of mkimage

Since U-Boot tools are being built anyways it's much nicer
to use them instead of relying on some of them bein installed
on build host (which might easily not be the case).

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

board/synopsys/axs10x/config.mk

@@ -18,6 +18,6 @@ else
 		--image $(srctree)/u-boot.bin \
 		--elf $(srctree)/u-boot
 endif
-	$(Q)mkimage -T script -C none -n 'uboot update script' \
+	$(Q)tools/mkimage -T script -C none -n 'uboot update script' \
 		-d $(srctree)/u-boot-update.txt \
 		$(srctree)/u-boot-update.img &> /dev/null

board/synopsys/hsdk/config.mk

@@ -6,6 +6,6 @@ bsp-generate: u-boot u-boot.bin
 	$(Q)python3 $(srctree)/board/$(BOARDDIR)/headerize-hsdk.py \
 		--arc-id 0x52 --image $(srctree)/u-boot.bin \
 		--elf $(srctree)/u-boot
-	$(Q)mkimage -T script -C none -n 'uboot update script' \
+	$(Q)tools/mkimage -T script -C none -n 'uboot update script' \
 		-d $(srctree)/u-boot-update.txt \
 		$(srctree)/u-boot-update.scr &> /dev/null