baytrail: use the setting in devicetree.cb to config USBPHY_COMPBG

USBPHY_COMPBG needs to be configured by project

BUG=chrome-os-partner:30690
BRANCH=none
TEST=emerge-rambi coreboot without problem
     checked the USBPHY_COMPBG is configured properly

Original-Change-Id: I05eee384d94cf5deeec14418bd78816df0b26a92
Original-Signed-off-by: Kane Chen <kane.chen@intel.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/208557
Original-Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>
(cherry picked from commit 20a9c0ab7ab180596821751110f0c0a35d3ff3a1)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I8bed3fa4e74e4bb4c93fa522d9df631bac2d9795
Reviewed-on: http://review.coreboot.org/8216
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/soc/intel/baytrail/ehci.c b/src/soc/intel/baytrail/ehci.c
index 5d1a4d8..bfdb61a 100644
--- a/src/soc/intel/baytrail/ehci.c
+++ b/src/soc/intel/baytrail/ehci.c
@@ -96,7 +96,8 @@
 	struct soc_intel_baytrail_config *config = dev->chip_info;
 	struct reg_script usb2_phy_script[] = {
 		/* USB3PHYInit() */
-		REG_IOSF_WRITE(IOSF_PORT_USBPHY, USBPHY_COMPBG, 0x4700),
+		REG_IOSF_WRITE(IOSF_PORT_USBPHY, USBPHY_COMPBG,
+			       config->usb2_comp_bg),
 		/* Per port phy settings, set in devicetree.cb */
 		REG_IOSF_WRITE(IOSF_PORT_USBPHY, USBPHY_PER_PORT_LANE0,
 			       config->usb2_per_port_lane0),