pcengines/apu1: Add CMOS/NVRAM support

Inspired by the Sage source code (itself from coreboot).

Change-Id: I4864923166efb200882d895c572d1ee060c71951
Signed-off-by: Maxime de Roucy <maxime.deroucy@gmail.com>
Reviewed-on: http://review.coreboot.org/11730
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/mainboard/pcengines/apu1/cmos.default

@@ -0,0 +1,5 @@
+last_boot=Fallback
+boot_option=Fallback
+multi_core=Enable
+debug_level=Spew
+baud_rate=115200