nb/intel/haswell/gma: Support boards that have DDI E connected

On an ASRock H81M-HDS neither libgfxinit, nor Linux, is able to
initialise the display when lanes are not configured to be shared
between DDI A and DDI E.

Intel's reference manual [1] states that the decision to share lanes
between DDI A and DDI E is "based on board configuration". Hence, add a
new field to the devicetree that boards can set. All existing Haswell
boards have this unset, thus taking a value of 0, so there is no change
to existing behaviour.

[1]: Intel Open Source Graphics Programmer's Reference Manual (PRM)
     Volume 2c: Command Reference: Registers (Haswell)
     https://01.org/linuxgraphics/documentation/hardware-specification-prms/2013-intel-core-processor-family

Change-Id: I6f7832293215d2b53e31b0a5c985e6098eb72f1b
Signed-off-by: Tristan Corrick <tristan@corrick.kiwi>
Reviewed-on: https://review.coreboot.org/29385
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions