p2771-0000: Add support for framebuffer carveouts

p2771-0000: Add support for framebuffer carveouts

If early firmware initialized the display hardware and the display
controllers are scanning out a framebuffer (e.g. a splash screen), make
sure to pass information about the memory location of that framebuffer
to the kernel before booting to avoid the kernel from using that memory
for the buddy allocator.

This same mechanism can also be used in the kernel to set up early SMMU
mappings and avoid SMMU faults caused by the display controller reading
from memory for which it has no mapping.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>