MLK-14857: mxc_hdmi: Set default mode a CEA mode

MLK-14857: mxc_hdmi: Set default mode a CEA mode

When using fb_find_mode from fbdev/core with a specified user more,
it will return a screeninfo structure with the pixclock corresponding to
a different refresh rate than the requested one. For example, for
1920x1080@60 it will return pixclock=5780. When we get the videmode for
this screeninfo, it will have a refresh of 59Hz, instead of 60Hz.
If we use this mode as default mode when EDID cannot be read, on a
monitor with fixed refresh rate of 60Hz, it won't work. Therefore, we
should save the default mode, the nearest mode from CEA modes defined by
our own driver (which will have the correct refresh rate and pixclock for
the requested resolution).

Signed-off-by: Robert Chiras <robert.chiras@nxp.com>