xhci: Increase STS_SAVE timeout in xhci_suspend()

After commit f7fac17c ("xhci: Convert xhci_handshake() to use
readl_poll_timeout_atomic()"), ASMedia xHCI may fail to suspend.

Although the algorithms are essentially the same, the old max timeout is
(usec + usec * time of doing readl()), and the new max timeout is just
usec, which is much less than the old one.

Increase the timeout to make ASMedia xHCI able to suspend again.

BugLink: https://bugs.launchpad.net/bugs/1844021
Fixes: f7fac17c ("xhci: Convert xhci_handshake() to use readl_poll_timeout_atomic()")
Cc: <stable@vger.kernel.org> # v5.2+
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/1570190373-30684-8-git-send-email-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci.c

@@ -1032,7 +1032,7 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
 	writel(command, &xhci->op_regs->command);
 	xhci->broken_suspend = 0;
 	if (xhci_handshake(&xhci->op_regs->status,
-				STS_SAVE, 0, 10 * 1000)) {
+				STS_SAVE, 0, 20 * 1000)) {
 	/*
 	 * AMD SNPS xHC 3.0 occasionally does not clear the
 	 * SSS bit of USBSTS and when driver tries to poll