ARM: mxs: Add Creative ZEN XFi3 board

Add STMP3780-based XFi3 board. This board is a small PMP device
sporting a CPU which was later rebranded to i.MX233 . Currently
supported is USB gadget mode and both external SD and internal
Phison SD-NAND bridge .

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Stefano Babic <sbabic@denx.de>