[P21]Phase in FactoryOta

- Phase in FactoryOta to P21

Bug: 182117971
Test: Forrest build
Change-Id: Ibd33c0c1295c420add15c708b43db2913fc55f36
diff --git a/device-common.mk b/device-common.mk
index d0e4ca1..f0b2bda 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -20,3 +20,6 @@
 PRODUCT_COPY_FILES += \
     frameworks/native/data/etc/android.hardware.telephony.carrierlock.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.hardware.telephony.carrierlock.xml
 
+# Factory OTA
+-include vendor/google/factoryota/client/factoryota.mk
+