MLK-14648: mxc: fix default modelist

MLK-14648: mxc: fix default modelist

When EDID read fails, the mxc_hdmi driver creates a default modelist
using a hard-coded list with CEA modes.
Every time the HDMI cable is plugged-in, it will destroy the current
modelist and recreate the list. The problem comes from fbcon, which
holds reference to current mode used for each framebuffer console. When
we destroy the modelist and send the new one, if the memory for the old
mode is overwritten it will try to find another mode, close to the old
one. Since the mode could be overwritten by something else there is a
high chance that the new selected mode to be different from the old one.
If the HDMI sink does not support the selected mode, IPU will fail to
deliver frames.
Since it's wrong to advertise as supported modes the modes from a
hard-coded list, just use one mode, which comes from cmdline.

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