mb/google/brya: Allow variants to choose CAR setup configuration

Lists of changes:
1. Create choice config to let ADL mb variants to pick the desire CAR
setup configuration between NEM and eNEM, where NEM and eNEM Kconfig
have selected its required IA SoC common CAR Kconfig to able to perform
the early boot configuration using CAR.
2. Lists of variants (kano, redrix, and felwinter) to drop
INTEL_CAR_NEM Kconfig select and choose eNEM.
3. Default CAR configuration for ADL mb is still NEM due to still using
older SoC skus without eNEM support enabled.

BUG=b:168820083
TEST=Able to build and boot P2 boards using eNEM mode.

Change-Id: Ibe94e6b82739ec65829859271622d904d75e978d
Signed-off-by: subratabanik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/59272
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>

0 files changed, 0 insertions, 0 deletions