drm/gma500: add support for atom e6xx lpc lvds i2c

add gpio bitbanging i2c adapter on LPC device of atom e6xx
gpu chipset to access lvds EDID
tested on SECO QuadMo747-E6xx-EXTREME Qseven platform

Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Jan Safrata <jan.nikitenko@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/gma500/psb_intel_drv.h b/drivers/gpu/drm/gma500/psb_intel_drv.h
index 336bd3a..860dd21 100644
--- a/drivers/gpu/drm/gma500/psb_intel_drv.h
+++ b/drivers/gpu/drm/gma500/psb_intel_drv.h
@@ -223,6 +223,7 @@
 extern void oaktrail_wait_for_INTR_PKT_SENT(struct drm_device *dev);
 extern void oaktrail_dsi_init(struct drm_device *dev,
 			   struct psb_intel_mode_device *mode_dev);
+extern void oaktrail_lvds_i2c_init(struct drm_encoder *encoder);
 extern void mid_dsi_init(struct drm_device *dev,
 		    struct psb_intel_mode_device *mode_dev, int dsi_num);