Snow bootblock (bloated/debug version)

This is the bloated Snow bootblock which includes:
- SPI driver
- UART, including requisite I2C, Maxim PMIC, and clock config code.
- Adjustments for magic offsets (id section, stack pointer address)

This is just a temporary solution until we have romstage loading.
Once that happens, we'll rip out all but the code necessary for
copying SPI ROM content into SRAM.

Change-Id: I2a11e272eb9b6f626b5d9783eabb4a720a1d06be
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2170
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/mainboard/google/snow/Kconfig

@@ -56,6 +56,10 @@ config MAINBOARD_VENDOR
 	string
 	default "Samsung"
 
+config BOOTBLOCK_MAINBOARD_INIT
+	string
+	default "mainboard/google/snow/bootblock.c"
+
 # SPL (second-phase loader) stuff
 config SPL_TEXT_BASE
 	hex