Staging: fbtft: Add support for the Ultrachip UC1611 LCD controller

This is a driver chip for 240x160 4-bit greyscale LCDs.
It is capable of 4-wire (8 bit) or 3-wire (9 bit) SPI that have both been
tested. (It also has a 6800 or 8080-style parallel interface, but I have
not included support for it.)

Signed-off-by: Henri Chain <henri.chain@eleves.ec-nantes.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>