veyron_*: Move PMIC_BUS to a Kconfig variable

This moves PMIC_BUS from each mainboard's board.h file to a per-
mainboard Kconfig variable. To prevent humans from forgetting to
set a valid value, an invalid default is set in the rk3288 Kconfig
and checked in rk808.c so that compilation will fail if the mainboard
Kconfig does not override it.

Originally, PMIC_BUS was only used by mainboard code as an argument
to RK808 PMIC functions. To conform to the generic RTC API, however,
the RK808 code needs to have the bus number globally defined somewhere
since the rtc_get() and rtc_set() functions don't take any args.

Since CONFIG_PMIC_BUS is globally visible, we no longer need to pass
bus number to the PMIC functions.

BUG=chrome-os-partner:34436
BRANCH=none
TEST=built and booted on Pinky

Signed-off-by: David Hendricks <dhendrix@chromium.org>
Change-Id: I73783878e507b2e7b1526dd2f81cfbdf8f1e2a55
Reviewed-on: https://chromium-review.googlesource.com/240203
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/9642
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
diff --git a/src/soc/rockchip/rk3288/Kconfig b/src/soc/rockchip/rk3288/Kconfig
index 95113f3..48ea7fc 100644
--- a/src/soc/rockchip/rk3288/Kconfig
+++ b/src/soc/rockchip/rk3288/Kconfig
@@ -37,4 +37,8 @@
 	string
 	default "soc/rockchip/rk3288/bootblock.c"
 
+config PMIC_BUS
+	int
+	default -1
+
 endif