drm/imx/ldb: convert to struct drm_edid

Prefer the struct drm_edid based functions for reading the EDID and
updating the connector.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/c1f1143b5aea14aea968cda6508b275b2f7246ea.1715691257.git.jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>