gs101: refactor changes into separate BoardConfig

thanks to @CalyxOS for remininding me about that

Change-Id: I66ac6344ad5d3a2534d67c0683ed944ebcec692b
diff --git a/BoardConfig-common.mk b/BoardConfig-common.mk
index a5e752d..bf3cc34 100644
--- a/BoardConfig-common.mk
+++ b/BoardConfig-common.mk
@@ -396,3 +396,5 @@
 BOARD_PVMFWIMAGE_PARTITION_SIZE := 0x00100000
 
 -include vendor/google_devices/gs-common/proprietary/BoardConfigVendor.mk
+
+include device/google/gs101/BoardConfig-omni.mk