Cleanup skiboot.mk

Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>
diff --git a/openpower/package/skiboot/skiboot.mk b/openpower/package/skiboot/skiboot.mk
index f2b85e2..6b7d6aa 100644
--- a/openpower/package/skiboot/skiboot.mk
+++ b/openpower/package/skiboot/skiboot.mk
@@ -18,34 +18,34 @@
 SKIBOOT_INSTALL_IMAGES = YES
 SKIBOOT_INSTALL_TARGET = NO
 
-ifeq ($(BR2_SKIBOOT_DEVICETREE),y)
-SKIBOOT_DEPENDENCIES += host-dtc
-endif
-
-SKIBOOT_MAKE_OPTS += CC="$(TARGET_CC)" LD="$(TARGET_LD)" \
-		     AS="$(TARGET_AS)" AR="$(TARGET_AR)" NM="$(TARGET_NM)" \
-		     OBJCOPY="$(TARGET_OBJCOPY)" OBJDUMP="$(TARGET_OBJDUMP)" \
-		     SIZE="$(TARGET_CROSS)size"
 
 ifeq ($(BR2_PACKAGE_SKIBOOT_EMBED_PAYLOAD),y)
 SKIBOOT_MAKE_OPTS += KERNEL=$(BINARIES_DIR)/$(LINUX_IMAGE_NAME)
 SKIBOOT_DEPENDENCIES += linux
 endif
 
-define SKIBOOT_BUILD_CMDS
-	$(TARGET_CONFIGURE_OPTS) SKIBOOT_VERSION=`cat $(SKIBOOT_VERSION_FILE)` \
-		$(TARGET_MAKE_ENV) $(MAKE) $(SKIBOOT_MAKE_OPTS) -C $(@D) all
+ifeq ($(BR2_SKIBOOT_DEVICETREE),y)
+SKIBOOT_DEPENDENCIES += host-dtc
+define SKIBOOT_BUILD_DEVICETREE
+	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D)/external/devicetree all
+endef
+define SKIBOOT_INSTALL_DEVICETREE
+	$(INSTALL) -D -m 644 $(@D)/external/devicetree/*.dtb $(BINARIES_DIR)
+endef
+endif
 
-	$(if $(BR2_SKIBOOT_DEVICETREE), $(TARGET_CONFIGURE_OPTS) \
-		$(TARGET_MAKE_ENV) $(MAKE) -C $(@D)/external/devicetree)
+# Pass Configure opts as env to not override Skiboot's
+# Additionally, Skiboot expects SKIBOOT_VERSION as env
+define SKIBOOT_BUILD_CMDS
+	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) \
+		SKIBOOT_VERSION=`cat $(SKIBOOT_VERSION_FILE)` \
+		$(MAKE) -C $(@D) $(SKIBOOT_MAKE_OPTS) all
+	$(SKIBOOT_BUILD_DEVICETREE)
 endef
 
 define SKIBOOT_INSTALL_IMAGES_CMDS
 	$(INSTALL) -D -m 755 $(@D)/skiboot.lid $(BINARIES_DIR)
-
-	$(if $(BR2_SKIBOOT_DEVICETREE), \
-		$(INSTALL) -D -m 644 \
-			$(@D)/external/devicetree/*.dtb $(BINARIES_DIR))
+	$(SKIBOOT_INSTALL_DEVICETREE)
 endef
 
 $(eval $(generic-package))