usb: host: xhci-rcar: Avoid long wait in xhci_reset()

The firmware of R-Car USB 3.0 host controller will control the reset.
So, if the xhci driver doesn't do firmware downloading (e.g. kernel
configuration is CONFIG_USB_XHCI_PLATFORM=y and CONFIG_USB_XHCI_RCAR
is not set), the reset of USB 3.0 host controller doesn't work
correctly. Then, the host controller will cause long wait in
xhci_reset() because the CMD_RESET bit of op_regs->command is not
cleared for 10 seconds.

So, this patch modifies the Kconfig to enable both CONFIG_USB_XHCI_PLATFORM
and CONFIG_USB_XHCI_RCAR.

Fixes: 4ac8918f (usb: host: xhci-plat: add support for the R-Car H2 and M2 xHCI controllers)
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>