drm/amd/display: Add visualconfirm module parameter

[Why]

Being able to configure visual confirm at boot or in cmdline is helpful
when debugging.

[How]

Add a module parameter to configure DC visual confirm, which works the
same way as the equivalent debugfs entry.

Signed-off-by: Leo Li <[e-mail]>
Reviewed-by: Rodrigo Siqueira <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

···
 extern int amdgpu_smu_pptable_id;
 extern uint amdgpu_dc_feature_mask;
 extern uint amdgpu_dc_debug_mask;
+extern uint amdgpu_dc_visual_confirm;
 extern uint amdgpu_dm_abm_level;
 extern int amdgpu_backlight;
 extern struct amdgpu_mgpu_info mgpu_info;

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

···
  */
 uint amdgpu_dc_feature_mask = 2;
 uint amdgpu_dc_debug_mask;
+uint amdgpu_dc_visual_confirm;
 int amdgpu_async_gfx_ring = 1;
 int amdgpu_mcbp;
 int amdgpu_discovery = -1;
···
  */
 MODULE_PARM_DESC(dcdebugmask, "all debug options disabled (default))");
 module_param_named(dcdebugmask, amdgpu_dc_debug_mask, uint, 0444);
+
+MODULE_PARM_DESC(visualconfirm, "Visual confirm (0 = off (default), 1 = MPO, 5 = PSR)");
+module_param_named(visualconfirm, amdgpu_dc_visual_confirm, uint, 0444);
 
 /**
  * DOC: abmlevel (uint)

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

···
 	if (amdgpu_dc_debug_mask & DC_FORCE_SUBVP_MCLK_SWITCH)
 		adev->dm.dc->debug.force_subvp_mclk_switch = true;
 
+	adev->dm.dc->debug.visual_confirm = amdgpu_dc_visual_confirm;
+
 	r = dm_dmub_hw_init(adev);
 	if (r) {
 		DRM_ERROR("DMUB interface failed to initialize: status=%d\n", r);