S6D1121 support

Hi Noralf,

I've created a simple driver for S6D1121 controller. I'm using ITDB02-2.4E module with LCD Adapter Kit, the name passed to fbtft_device is itdb24 (fbtft_device verbose=0 name=itdb24 rotate=270 fps=25). Maybe you'll be interested to merge this into your project.

Best regards,
Roman