kernel: Handle GKI modules

All devices lauching with Android 13 (and above) must include
a system_dlkm partition, where GKI modules should reside.

Android 13 build system only supports providing prebuilt modules,
by pointing BOARD_SYSTEM_DLKM_SRC to the modules source folder.
Google will introduce BOARD_SYSTEM_KERNEL_MODULES for Android 14,
so take a step forward and use that macro to exclude the listed
modules from the usual vendor DLKM partition and place them into
the GKI module partition.

Note that the GKI modules are placed into lib/modules/androidX-Y.Z,
as defined by Google and observed in system_dlkm_modprobe script.

Change-Id: I2b1644479788cb5c9568cac738202b1d55fc28d7