Support LCDIF for mx7dsabresd board:
1. Add pinmux settings
2. Add VIDEO related macro definition and videomode env settings.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Adrian Alonso <aalonso@freescale.com>