drm/panel: ilitek-ili9882t: Add support for Ilitek IL79900A-based panels

drm/panel: ilitek-ili9882t: Add support for Ilitek IL79900A-based panels

The Ilitek IL79900A display controller is similar to the ILI9882T and can
be supported within the existing `panel-ilitek-ili9882t.c` driver.

This patch extends the ILI9882T driver to handle IL79900A-based panels,
such as the Tianma TL121BVMS07-00. The IL79900A uses a similar command
sequence and initialization flow, with minor differences in power supply
configuration and timing.

Signed-off-by: Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251031100447.253164-3-yelangyan@huaqin.corp-partner.google.com