arch/x86/acpi: Add DMAR RMRR helper functions

Add DMAR RMRR table entry and helper functions, using the existing
DRHD functions as a model. As the DRHD device scope (DS) functions
aren't DRHD-specific, genericize them to be used with RMRR tables as
well. Correct DRHD bar size to match table entry in creator function,
as noted in comments from patchset below.

Adapted from/supersedes https://review.coreboot.org/25445

Change-Id: I912b1d7244ca4dd911bb6629533d453b1b4a06be
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/27269
Reviewed-by: Youness Alaoui <snifikino@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Jay Talbott <JayTalbott@sysproconsulting.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
8 files changed