drm/amd/display: Decrease messaging about DP alt mode state to debug

Currently plugging in a USB-C device that issues an HPD will emit
a warning level message `DP Alt mode state on HPD: %d`.

This is needlessly noisy for most people, decrease it to debug so
that it can be turned on by dynamic debug as needed.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -837,7 +837,7 @@ static bool wait_for_entering_dp_alt_mode(struct dc_link *link)
 		return true;
 
 	is_in_alt_mode = link->link_enc->funcs->is_in_alt_mode(link->link_enc);
-	DC_LOG_WARNING("DP Alt mode state on HPD: %d\n", is_in_alt_mode);
+	DC_LOG_DC("DP Alt mode state on HPD: %d\n", is_in_alt_mode);
 
 	if (is_in_alt_mode)
 		return true;