wifi: Isolate wifi configurations for customization.

add gs101/wifi/BoardConfig-wifi.mk.

Bug: 208159314
Test: ifconfig after attempting STA+SAP concurrency.
Change-Id: I5f1d52c36da220361aff2840596c9fb95fc40719
diff --git a/whitefin/BoardConfig.mk b/whitefin/BoardConfig.mk
index e042336..5b5a07a 100644
--- a/whitefin/BoardConfig.mk
+++ b/whitefin/BoardConfig.mk
@@ -21,4 +21,5 @@
 BOARD_BOOTCONFIG += androidboot.selinux=permissive
 
 include device/google/gs101/BoardConfig-common.mk
+include device/google/gs101/wifi/BoardConfig-wifi.mk
 -include vendor/google_devices/gs101/prebuilts/BoardConfigVendor.mk