drm/panel: jh057n00900: Print error code on all DRM_DEV_ERROR()s

Most of them had these already but two mere missing. This eases
debugging.

Signed-off-by: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/6b237a570cb368dc4471fb8feb3a0441813cd576.1564146727.git.agx@sigxcpu.org