Unset ENABLE_PREOPT when DISABLE_PREOPT is set

Instead of TARGET_BUILD_APPS, introduce DISABLE_PREOPT,
which is true when TARGET_BUILD_UNBUNDLED_IMAGE or TARGET_BUILD_APPS is set.

Test: TARGET_BUILD_UNBUNDLED_IMAGE=true m vendorimage and then
      check if there is no preopt
Bug: 160390776

Change-Id: Id27030e602a29ebd438678270db13744dd145143
diff --git a/core/config.mk b/core/config.mk
index f9bb873..1a0a418 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -526,13 +526,17 @@
 .KATI_READONLY := ALLOW_MISSING_DEPENDENCIES
 
 TARGET_BUILD_USE_PREBUILT_SDKS :=
+DISABLE_PREOPT :=
 ifneq (,$(TARGET_BUILD_APPS)$(TARGET_BUILD_UNBUNDLED_IMAGE))
+  DISABLE_PREOPT := true
   ifndef UNBUNDLED_BUILD_SDKS_FROM_SOURCE
     TARGET_BUILD_USE_PREBUILT_SDKS := true
   endif
 endif
 
-.KATI_READONLY := TARGET_BUILD_USE_PREBUILT_SDKS
+.KATI_READONLY := \
+  TARGET_BUILD_USE_PREBUILT_SDKS \
+  DISABLE_PREOPT \
 
 prebuilt_sdk_tools := prebuilts/sdk/tools
 prebuilt_sdk_tools_bin := $(prebuilt_sdk_tools)/$(HOST_OS)/bin