device-common: include Pixel common MM mk file

This will enable zram and Pixel common config

Test: confirmed first writeback work via dumpsys jobscheduler | grep Zram
      check watermark_boost_factor
Bug: 190571517
Bug: 189938926
Bug: 190732106
Signed-off-by: Martin Liu <liumartin@google.com>
Change-Id: I1a475ea5481d21c7f9fa14eb5f01c6d6802def72
diff --git a/device-common.mk b/device-common.mk
index 345ee30..191ed2f 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -29,3 +29,6 @@
 
 PRODUCT_PRODUCT_PROPERTIES += \
     persist.vendor.testing_battery_profile=2
+
+# ZramWriteback
+-include hardware/google/pixel/mm/device_gki.mk