drm/msm/dp: fix runtime PM leak on connect failure

Make sure to balance the runtime PM usage counter (and suspend) before
returning on connect failures (e.g. DPCD read failures after a spurious
connect event or if link training fails).

Fixes: 5814b8bf ("drm/msm/dp: incorporate pm_runtime framework into DP driver")
Cc: stable@vger.kernel.org      # 6.8
Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/582746/
Link: https://lore.kernel.org/r/20240313164306.23133-3-johan+linaro@kernel.orgSigned-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

drivers/gpu/drm/msm/dp/dp_display.c

@@ -572,6 +572,7 @@ static int dp_hpd_plug_handle(struct dp_display_private *dp, u32 data)
 	ret = dp_display_usbpd_configure_cb(&pdev->dev);
 	if (ret) {	/* link train failed */
 		dp->hpd_state = ST_DISCONNECTED;
+		pm_runtime_put_sync(&pdev->dev);
 	} else {
 		dp->hpd_state = ST_MAINLINK_READY;
 	}