rockchip: support pwm regulator

BUG=None
TEST=Boot Veyron Pinky and test the VDD_LOG

Original-Change-Id: Ie2eef918e04ba0e13879e915b0b0bef44aef550e
Original-Signed-off-by: huang lin <hl@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/219753
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Julius Werner <jwerner@chromium.org>

Change-Id: I444b47564d90b3480b351fdd8460e5b94e71927c
(cherry picked from commit 4491d9c4037161fd8c4cc40856167bf73182fda6)
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9240
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
diff --git a/src/soc/rockchip/rk3288/Makefile.inc b/src/soc/rockchip/rk3288/Makefile.inc
index aa1f002..95d72c9 100644
--- a/src/soc/rockchip/rk3288/Makefile.inc
+++ b/src/soc/rockchip/rk3288/Makefile.inc
@@ -51,6 +51,7 @@
 romstage-y += spi.c
 romstage-y += media.c
 romstage-y += sdram.c
+romstage-y += pwm.c
 
 ramstage-y += soc.c
 ramstage-y += cbmem.c
@@ -62,6 +63,7 @@
 ramstage-y += gpio.c
 ramstage-y += media.c
 ramstage-y += rk808.c
+ramstage-y += pwm.c
 ramstage-$(CONFIG_DRIVERS_UART) += uart.c
 
 $(objcbfs)/bootblock.raw.elf: $(objcbfs)/bootblock.elf