google/slippy: clean up NGI and move to libgfxinit
- remove old, buggy NGI code from falco/peppy variants
- remove superfluous INTEL_DP/INTEL_DDI configs, since already
selected by northbridge/haswell
- always use libgfxinit when use native init config selected
- enable NGI/libgfxinit for all slippy variants
The reset of the old Haswell NGI code will be cleaned up in
a subsequent patchset.
Test: select MAINBOARD_DO_NATIVE_VGA_INIT, observe panel init
using SeaBIOS and Tianocore payloads on peppy, wolf variants
Change-Id: Id5727cad7f714ffa57e77e2a25505e3c28f55237
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/18824
Tested-by: build bot (Jenkins)
Reviewed-by: Nico Huber <nico.h@gmx.de>