drm/panel: add panel driver for Elida KD35T133 panels

drm/panel: add panel driver for Elida KD35T133 panels

Panel driver for the KD35T133 display from Elida, used for example
in the rk3326-based Odroid Go Advance handheld.

changes in v3:
- add missing return value assignment (Francesco)
- re-sort header includes (Sam)
changes in v2:
- rename dsi_generic_write_seq macro to dsi_dcs_write_seq to honor
  the underlying mipi_dsi_dcs_write (Robin)

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200229151506.750242-3-heiko@sntech.de