new approach to graphics memory management:
the kernel driver never really cared about the size of stolen memory
directly. that was only to figure out the maximum allocation
to place the hardware cursor image somewhere at the end of the
allocation done by bios.
qu7uux's gm965 bios however wont steal enougth memory for his
native resolution so we have todo it manually.
the userspace igfx driver will figure out how much the bios
allocated by looking at the gtt only. then extend the memory by
creating a "fixed" physical segment.
the kernel driver allocates the memory for the cursor image
from normal kernel memory, and just maps it into the gtt at the
end of the virtual kernel framebuffer aperture.
thanks to qu7uux for the patch.
add support for edp, dp and hdmi on haswell and haswell ult.
vga, dvi and specific configurations like ulx are unimplemented.
remaining issue: edp link training always fails (time out).
given that the igfx driver doesnt provide any acceleration functions
and drawing is usually faster with double buffering as it eleminates
reads over the pci bus, enable softscreen by default.
initially, pio was used to access registers so i didnt need
a kernel driver for initial testing.
pio does not work under efi, so use mmio to access registers.
