cpu/intel/car/non-evict: Improve a few things

This improve the following:
- Improve readability for clearing fixed MTRR's
- Compute PHYSMASK high during runtime
- Cache the whole ROM_SIZE instead of XIP_ROM_SIZE

Change-Id: Ifaed96b41fab973fa541de1c4f005d6f0af5254f
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/26790
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
1 file changed