usb: host: xhci-rcar: Fix timeout in xhci_suspend()

When a USB device is connected to the host controller and
the system enters suspend, the following error happens
in xhci_suspend():

	xhci-hcd ee000000.usb: WARN: xHC CMD_RUN timeout

Since the firmware/internal CPU control the USBSTS.STS_HALT
and the process speed is down when the roothub port enters U3,
long delay for the handshake of STS_HALT is neeed in xhci_suspend().
So, this patch adds to set the XHCI_SLOW_SUSPEND.

Fixes: 435cc113 ("usb: host: xhci-plat: set resume_quirk() for R-Car controllers")
Cc: <stable@vger.kernel.org> # v4.12+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1564734815-17964-1-git-send-email-yoshihiro.shimoda.uh@renesas.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-rcar.c

@@ -238,10 +238,15 @@ int xhci_rcar_init_quirk(struct usb_hcd *hcd)
 	 * pointers. So, this driver clears the AC64 bit of xhci->hcc_params
 	 * to call dma_set_coherent_mask(dev, DMA_BIT_MASK(32)) in
 	 * xhci_gen_setup().
+	 *
+	 * And, since the firmware/internal CPU control the USBSTS.STS_HALT
+	 * and the process speed is down when the roothub port enters U3,
+	 * long delay for the handshake of STS_HALT is neeed in xhci_suspend().
 	 */
 	if (xhci_rcar_is_gen2(hcd->self.controller) ||
-			xhci_rcar_is_gen3(hcd->self.controller))
-		xhci->quirks |= XHCI_NO_64BIT_SUPPORT;
+			xhci_rcar_is_gen3(hcd->self.controller)) {
+		xhci->quirks |= XHCI_NO_64BIT_SUPPORT | XHCI_SLOW_SUSPEND;
+	}
 
 	if (!xhci_rcar_wait_for_pll_active(hcd))
 		return -ETIMEDOUT;