Revert MMIO space writes on shutdown as needed

Reversible MMIO space writes now use rmmio_write*().
Reversible PCI MMIO space writes now use pci_rmmio_write*().
If a MMIO value needs to be queued for restore without writing it,
use rmmio_val*().
MMIO space writes which are one-shot (e.g. communication with some chip)
should continue to use the permanent mmio_write* variants.

Corresponding to flashrom svn r1292.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>

David tested it successfully on some NM10/ICH7 platforms which switch
between SPI and LPC targets (x86 BIOS ROM vs. EC firmware ROM).

Acked-by: David Hendricks <dhendrix@google.com>
5 files changed