drm/panel: s6e63m0: Fix up DRM_DEV* regression

Ooops the panel drivers stopped to use DRM_DEV* messages
and we predictably create errors by merging code that
still use it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: David Airlie <airlied@linux.ie>
Link: https://patchwork.freedesktop.org/patch/msgid/20200906132903.5739-1-linus.walleij@linaro.org