build: standardize BUILD_ID featurization

CRs-fixed: 287594

Change-Id: Id553e01da6da24a718bce24a4a8a357d64598d09
diff --git a/AndroidBoot.mk b/AndroidBoot.mk
index c5fa6a5..53959fe 100644
--- a/AndroidBoot.mk
+++ b/AndroidBoot.mk
@@ -3,7 +3,7 @@
 TARGET_BOOTLOADER := $(PRODUCT_OUT)/appsboot.mbn
 BOOTLOADER_OUT := $(TOP)/$(TARGET_OUT_INTERMEDIATES)/BOOTLOADER_OBJ
 
-ifeq ($(BUILD_ID),HONEYCOMB)
+ifeq ($(call is-flavor,HONEYCOMB),true)
 CROSS_TOOL := ../../../prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/arm-eabi-
 else
 CROSS_TOOL := ../../../prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/bin/arm-eabi-