MKBOOTIMG override were missing in two places

The change follows the patten found in "Package OTA" and other places
to allow for overriding the mkbootimg command.

Now pass MKBOOTIMG variable to get make_recovery_patch and add_image_to_target
to use the tool set in BOARD_CUSTOM_MKBOOTIMG for boot/recovery image
generation.

Change-Id: I78533c25e87c2750eb24ac1bf39e4b7ca321a441
diff --git a/core/Makefile b/core/Makefile
index 478c966..796af42 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1450,7 +1450,7 @@
 	$(hide) echo "oem_fingerprint_properties=$(OEM_THUMBPRINT_PROPERTIES)" >> $(zip_root)/META/misc_info.txt
 endif
 	$(call generate-userimage-prop-dictionary, $(zip_root)/META/misc_info.txt)
-	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
+	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH MKBOOTIMG=$(MKBOOTIMG) \
 	    ./build/tools/releasetools/make_recovery_patch $(zip_root) $(zip_root)
 	@# Zip everything up, preserving symlinks
 	$(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)
@@ -1461,7 +1461,7 @@
 	$(hide) zipinfo -1 $@ | awk 'BEGIN { FS="BOOT/RAMDISK/" } /^BOOT\/RAMDISK\// {print $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/boot_filesystem_config.txt
 	$(hide) zipinfo -1 $@ | awk 'BEGIN { FS="RECOVERY/RAMDISK/" } /^RECOVERY\/RAMDISK\// {print $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/recovery_filesystem_config.txt
 	$(hide) (cd $(zip_root) && zip -q ../$(notdir $@) META/*filesystem_config.txt)
-	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH \
+	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH MKBOOTIMG=$(MKBOOTIMG) \
 	    ./build/tools/releasetools/add_img_to_target_files -p $(HOST_OUT) $@
 
 .PHONY: target-files-package