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/mid_bios.c b/drivers/gpu/drm/gma500/mid_bios.c
index b2a790b..850cd3f 100644
--- a/drivers/gpu/drm/gma500/mid_bios.c
+++ b/drivers/gpu/drm/gma500/mid_bios.c
@@ -118,20 +118,20 @@
 					dev_priv->platform_rev_id);
 }
 
-struct vbt_header {
+struct mid_vbt_header {
 	u32 signature;
 	u8 revision;
 } __packed;
 
 /* The same for r0 and r1 */
 struct vbt_r0 {
-	struct vbt_header vbt_header;
+	struct mid_vbt_header vbt_header;
 	u8 size;
 	u8 checksum;
 } __packed;
 
 struct vbt_r10 {
-	struct vbt_header vbt_header;
+	struct mid_vbt_header vbt_header;
 	u8 checksum;
 	u16 size;
 	u8 panel_count;
@@ -281,7 +281,7 @@
 	struct drm_device *dev = dev_priv->dev;
 	u32 addr;
 	u8 __iomem *vbt_virtual;
-	struct vbt_header vbt_header;
+	struct mid_vbt_header vbt_header;
 	struct pci_dev *pci_gfx_root = pci_get_bus_and_slot(0, PCI_DEVFN(2, 0));
 	int ret = -1;