dt-bindings: display: panel: mipi-dbi-spi: add Saef SF-TC154B

dt-bindings: display: panel: mipi-dbi-spi: add Saef SF-TC154B

The Saef SF-TC154B is a 1.54 inch 240x240 square panel with a MIPI DBI
compatible interface. The panel is used on the Anbernic RG-Nano
handheld gaming device.

The initialization of the panel requires a firmware binary which can
be made with the mipi-dbi-cmd[1] tool. The command sequence needed
can be found in both source[2] and binary form[3].

[1]: https://github.com/notro/panel-mipi-dbi
[2]: https://github.com/macromorgan/panel-mipi-dbi-firmware/raw/main/saef%2Csftc154b.txt
[3]: https://github.com/macromorgan/panel-mipi-dbi-firmware/raw/main/saef%2Csftc154b.bin

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://lore.kernel.org/r/20230828181941.1609894-3-macroalpha82@gmail.com
Signed-off-by: Rob Herring <robh@kernel.org>