[U-Boot] Add video support for mx51evk

[Frias Renato-B13784]

Hello Stefano,

This is my first post to the list, I work as Field Engineer for
Freescale, 
based in Brazil.

I'll be submitting couple patches to add support for the wvga lcd on the

mx51evk board, these are based on the work you did for vision2 board.

However, in order to add support for the second display inteface on the
imx51,
I had to change the Framebuffer driver. Thus, support for vision2 will
break,
to restore it all is needed is to add couple arguments to mx51_fb_init
call. 

Please review the patches and let me know if I should have done things
in a
different way.

There is also a second issue where I would like to know your thoughts.
Very 
early on system initialization, when LCD is enabled, there is a call to 
"lcd_setmem" from board.c. By that time, the video variables,
"panel_info", are
not set yet. Thus U-Boot doesn't reserve the appropriate amount of
memory for 
the display. I was going to set "panel_info" variable on mx51evk.c, but
I would like to know how you solved it for vision2 first.  

Thanks!
Renato Frias