mcs: allow compilation without networking for usbwriter

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

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: blank displays at poweroff, wait for power-on request

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: lock console before blanking

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mcs: configure SD3_DAT4 as input to detect 4/5-wire touch screen

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

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