gma500/cdv: Add eDP support

Introduce the eDP support into the driver.

This has been reworked a bit because kernel driver proper uses encoder/connectors
while the legacy Intel driver uses the old output stuff.

It also diverges on the backlight handling. The legacy Intel driver adds a panel
abstraction based upon the i915 one. It's only really used for backlight bits
and we have a perfectly good backlight abstraction which can extend instead.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
[ported to upstream driver, redid backlight abstraction]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 2de6b1f..884ba73 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -768,6 +768,9 @@
 			crtc_mask = (1 << 0) | (1 << 1);
 			clone_mask = (1 << INTEL_OUTPUT_DISPLAYPORT);
 			break;
+		case INTEL_OUTPUT_EDP:
+			crtc_mask = (1 << 1);
+			clone_mask = (1 << INTEL_OUTPUT_EDP);
 		}
 		encoder->possible_crtcs = crtc_mask;
 		encoder->possible_clones =