drm/panel: ej030na: Make use of the helper function dev_err_probe()

drm/panel: ej030na: Make use of the helper function dev_err_probe()

When possible use dev_err_probe help to properly deal with the
PROBE_DEFER error, the benefit is that DEFER issue will be logged
in the devices_deferred debugfs file.
And using dev_err_probe() can reduce code size, and the error value
gets printed.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210916104225.11111-1-caihuoqing@baidu.com