ANDROID: GKI: Enable system_dlkm build for gki

Update GKI build configs to build system_dlkm.img.

Add an empty system_dlkm modules list file at:
android/gki_system_dlkm_modules

Bug: 200082547
Bug: 214445388
Test: TH
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
Change-Id: Ia11b48d6033a39479d71c90159c74809a874893d