Add CWC hookswitch driver (virtual keyboard)

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
add imx6q-nitrogen6x-cwc device tree

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nitrogen6x: defconfig: add CWC_HOOKSWITCH driver

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>