drm/i915/gvt: changed DDI mode emulation type

changed gvt display transcode DDI mode from DP_SST to
DVI to address below calltrace issue during guest booting
up which is caused by zero dotclock initial value with DP_SST
mode. transcode DVI mode emulation also align with native with DP
connection.

[drm:drm_calc_timestamping_constants]
ERROR crtc 41: Can't calculate constants, dotclock = 0!

WARNING: at drivers/gpu/drm/drm_vblank.c:620
drm_calc_vbltimestamp_from_scanoutpos

Call Trace:
? drm_calc_timestamping_constants+0x144/0x150 [drm]
drm_get_last_vbltimestamp+0x54/0x90 [drm]
drm_reset_vblank_timestamp+0x59/0xd0 [drm]
drm_crtc_vblank_on+0x7b/0xd0 [drm]
intel_modeset_setup_hw_state+0xb67/0xfd0 [i915]
? gen2_read32+0x110/0x110 [i915]
? drm_modeset_lock+0x30/0xa0 [drm]
intel_modeset_init+0x794/0x19d0 [i915]
? intel_setup_gmbus+0x232/0x2e0 [i915]
i915_driver_load+0xb4a/0xf40 [i915]
Signed-off-by: Xiaolin Zhang <xiaolin.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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

@@ -196,7 +196,7 @@ static void emulate_monitor_status_change(struct intel_vgpu *vgpu)
 			~(TRANS_DDI_BPC_MASK | TRANS_DDI_MODE_SELECT_MASK |
 			TRANS_DDI_PORT_MASK);
 		vgpu_vreg_t(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) |=
-			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DP_SST |
+			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DVI |
 			(PORT_B << TRANS_DDI_PORT_SHIFT) |
 			TRANS_DDI_FUNC_ENABLE);
 		if (IS_BROADWELL(dev_priv)) {
@@ -216,7 +216,7 @@ static void emulate_monitor_status_change(struct intel_vgpu *vgpu)
 			~(TRANS_DDI_BPC_MASK | TRANS_DDI_MODE_SELECT_MASK |
 			TRANS_DDI_PORT_MASK);
 		vgpu_vreg_t(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) |=
-			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DP_SST |
+			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DVI |
 			(PORT_C << TRANS_DDI_PORT_SHIFT) |
 			TRANS_DDI_FUNC_ENABLE);
 		if (IS_BROADWELL(dev_priv)) {
@@ -236,7 +236,7 @@ static void emulate_monitor_status_change(struct intel_vgpu *vgpu)
 			~(TRANS_DDI_BPC_MASK | TRANS_DDI_MODE_SELECT_MASK |
 			TRANS_DDI_PORT_MASK);
 		vgpu_vreg_t(vgpu, TRANS_DDI_FUNC_CTL(TRANSCODER_A)) |=
-			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DP_SST |
+			(TRANS_DDI_BPC_8 | TRANS_DDI_MODE_SELECT_DVI |
 			(PORT_D << TRANS_DDI_PORT_SHIFT) |
 			TRANS_DDI_FUNC_ENABLE);
 		if (IS_BROADWELL(dev_priv)) {