Update all Librems except L1UM (but including L1UM v2) to Linux 6.1.8.
Use coreboot native graphics init. Raise maximum framebuffer size for
laptops to 3840x2160 (desktops default to this, but laptops default
to a lower value). Remove DRM modules from Linux 6.1.8 and add EFIFB.
Remove Heads kernel command line options relating to IOMMU and i915,
which are no longer needed. Remove OS kernel options relating to
IOMMU.
For Librem 13/15/14/Mini, this fixes issues booting with 4K displays
attached, which were resulting in crashes due to the framebuffer memory
not being reserved properly. memtest86+ now passes with a 4K display
attached.
For Librem L1UM v2, framebuffer boot now works.
Librem L1UM remains on Linux 5.10 with Heads kernel graphic init
(framebuffer boot still does not work). coreboot 4.11 has native
graphics init for Aspeed, but only in text mode. Backporting the
linear framebuffer support appears to be possible - the patch applied
cleanly - but it did not work initially and will need more
investigation.
Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>