soc/{apl,glk}: Allow to select the primary graphics device

Allow to select the primary graphics device between the IGD and the
external PCIe GPU depending on the ONBOARD_VGA_IS_PRIMARY config.
The option sets the priority only. This means that if a high priority
is set for an external PCI device and it is not connected/not enabled,
then the device with a lower priority will be used, in our case it is
IGD.

TEST = Set PRIMARY_PCI and boot Linux on the Kontron mAL10 [1] with
the miniPCIe video adapter on the Silicon Motion SM750 controller. As
a result, the display connected to an external GPU device shows the
Tianocore logo + setup menu and the desktop.

[1] https://review.coreboot.org/c/coreboot/+/39133

Change-Id: Idcd117217cf412ee0722aff52db4b3c8ec2a226c
Signed-off-by: Maxim Polyakov <max.senia.poliak@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39374
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>

0 files changed, 0 insertions, 0 deletions