drm/i915/gvt: make dpcd_fix_data supports DP1.2

GVT-g will emulate a fixed DPCD data to VM for DP/eDP panel. Update
this data to latest DP1.2 with the maximum lane bandwidth of 5.4G/s
to support 4K resolution in VM.

V3: modify patch comment
V2: add inline comment to describe the dpcd_fix_data.
Signed-off-by: Pei Zhang <pei.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/display.c

@@ -161,8 +161,9 @@ static unsigned char virtual_dp_monitor_edid[GVT_EDID_NUM][EDID_SIZE] = {
 
 #define DPCD_HEADER_SIZE        0xb
 
+/* let the virtual display supports DP1.2 */
 static u8 dpcd_fix_data[DPCD_HEADER_SIZE] = {
-	0x11, 0x0a, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+	0x12, 0x014, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 };
 
 static void emulate_monitor_status_change(struct intel_vgpu *vgpu)