drm/amd/display: Remove the unused variable pre_connection_type

Variable pre_connection_type is not effectively used, so delete it.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4031Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/link/link_detection.c

@@ -859,7 +859,6 @@ static bool detect_link_and_local_sink(struct dc_link *link,
 	struct dc_sink *prev_sink = NULL;
 	struct dpcd_caps prev_dpcd_caps;
 	enum dc_connection_type new_connection_type = dc_connection_none;
-	enum dc_connection_type pre_connection_type = dc_connection_none;
 	const uint32_t post_oui_delay = 30; // 30ms
 
 	DC_LOGGER_INIT(link->ctx->logger);
@@ -896,7 +895,6 @@ static bool detect_link_and_local_sink(struct dc_link *link,
 
 	link_disconnect_sink(link);
 	if (new_connection_type != dc_connection_none) {
-		pre_connection_type = link->type;
 		link->type = new_connection_type;
 		link->link_state_valid = false;