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: NMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/Kconfig

@@ -37,6 +37,7 @@ config USB_ARCH_HAS_EHCI
 	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