mmc: rtsx_usb_sdmmc: Enable runtime PM autosuspend

Enable runtime PM autosuspend for the rtsx_usb_sdmmc driver to avoid the
device being runtime suspended and runtime resumed between each request.
Let's use a default timeout of 50ms, to be consistent with other mmc hosts.

Cc: Ritesh Raj Sarraf <rrs@researchut.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/rtsx_usb_sdmmc.c

@@ -1374,6 +1374,8 @@ static int rtsx_usb_sdmmc_drv_probe(struct platform_device *pdev)
 
 	mutex_init(&host->host_mutex);
 	rtsx_usb_init_host(host);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
 	pm_runtime_enable(&pdev->dev);
 
 #ifdef RTSX_USB_USE_LEDS_CLASS
@@ -1428,6 +1430,7 @@ static int rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev)
 
 	mmc_free_host(mmc);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
 	platform_set_drvdata(pdev, NULL);
 
 	dev_dbg(&(pdev->dev),