Disable CEA mode check in mxc_hdmi.c (allow any EDID resolution)

This fixes problems with DVI monitors connected to the HDMI port
via a DVI <-> HDMI cable. With dvi monitors, the list of CEA modes
is always zero, preventing modes higher than 640x480 to be used.
This patch disables the CEA mode check.

Patch from: https://github.com/Freescale/meta-fsl-arm-extra/blob/master/recipes-kernel/linux/linux-cubox-i-3.0.35/mxc_hdmi-dont-require-cea-mode.patch