The SSD16xx driver currently hard-codes a couple of register overrides
that aren't relevant or even correct for many devices. Make them
optional device tree properties instead.
Note that this changes the behavior for panels that expect
SSD16XX_CMD_DUMMY_LINE and SSD16XX_CMD_GATE_LINE_WIDTH to be set by
the driver. This fixes a bug where the incorrect value
was written to all SSD16xx panels except for GDEH0213B1 and GDEH029A1.
The overlay files for devices that need dummy line and gate line width
to be specified have been updated as a part of this commit.
Signed-off-by: Andreas Sandberg <andreas@sandberg.uk>
a43fd92c4e