Do not disable factory build under PDK

This is related to commit a1712e.
Some PDKs need the factory build under PDK. If you want to disable the factory
build under PDK, use TARGET_NO_FACTORY in your device's BoardConfig.mk

Change-Id: I5e208836918ffd737951d3fb1f54c560d2b93641
diff --git a/core/tasks/factory_bundle.mk b/core/tasks/factory_bundle.mk
index 5c5adc3..054a52a 100644
--- a/core/tasks/factory_bundle.mk
+++ b/core/tasks/factory_bundle.mk
@@ -16,6 +16,9 @@
 
 ifeq (,$(ONE_SHOT_MAKEFILE))
 ifneq ($(TARGET_BUILD_PDK),true)
+  TARGET_BUILD_FACTORY=true
+endif
+ifeq ($(TARGET_BUILD_FACTORY),true)
 
 # PRODUCT_FACTORY_RAMDISK_MODULES consists of "<module_name>:<install_path>[:<install_path>...]" tuples.
 # <install_path> is relative to the staging directory for the bundle.
diff --git a/core/tasks/factory_ramdisk.mk b/core/tasks/factory_ramdisk.mk
index 579fd6a..00fcdde 100644
--- a/core/tasks/factory_ramdisk.mk
+++ b/core/tasks/factory_ramdisk.mk
@@ -16,6 +16,9 @@
 
 ifeq (,$(ONE_SHOT_MAKEFILE))
 ifneq ($(TARGET_BUILD_PDK),true)
+  TARGET_BUILD_FACTORY=true
+endif
+ifeq ($(TARGET_BUILD_FACTORY),true)
 
 # PRODUCT_FACTORY_RAMDISK_MODULES consists of "<module_name>:<install_path>[:<install_path>...]" tuples.
 # <install_path> is relative to TARGET_FACTORY_RAMDISK_OUT.