USB: select USB_ARCH_HAS_EHCI for MXS

Commit 09f6ffde (USB: EHCI: fix build error by making ChipIdea host a
normal EHCI driver) introduced a dependency on USB_EHCI_HCD for the
chipidea USB host driver, that in turns depends on USB_ARCH_HAS_EHCI.

If this symbol is not set for MXS, the MXS boards are not able to use
the chipidea driver anymore.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 4c90b510..640ae6c 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -37,6 +37,7 @@
 	default y if ARCH_W90X900
 	default y if ARCH_AT91
 	default y if ARCH_MXC
+	default y if ARCH_MXS
 	default y if ARCH_OMAP3
 	default y if ARCH_CNS3XXX
 	default y if ARCH_VT8500