vboot: allow for non-memory-mapped VBOOT regions

Depending on the platform the underlying regions vboot requires
may not be accessible through a memory-mapped interface. Allow
for non-memory-mapped regions by providing a region request
abstraction. There is then only a few touch points in the code to
provide compile-time decision making no how to obtain a region.

For the vblocks a temporary area is allocated from cbmem. They
are then read from the SPI into the temporarily buffer.

BUG=chrome-os-partner:27094
BRANCH=None
TEST=Built and booted a rambi with vboot verification.

Original-Change-Id: I828a7c36387a8eb573c5a0dd020fe9abad03d902
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/190924
Original-Reviewed-by: Hung-Te Lin <hungte@chromium.org>
(cherry picked from commit aee0280bbfe110eae88aa297b433c1038c6fe8a3)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Ia020d1eebad753da950342656cd11b84e9a85376
Reviewed-on: http://review.coreboot.org/7709
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/drivers/spi/Kconfig

@@ -26,6 +26,13 @@ config SPI_FLASH
 
 if SPI_FLASH
 
+config SPI_FLASH_MEMORY_MAPPED
+	bool
+	default y if ARCH_X86
+	default n if !ARCH_X86
+	help
+	  Inform system if SPI is memory-mapped or not.
+
 config SPI_FLASH_SMM
 	bool "SPI flash driver support in SMM"
 	default n