drm/panel-simple: add Evervision VGG644804 panel entry

drm/panel-simple: add Evervision VGG644804 panel entry

Timings taken from the datasheet, although sometimes there are just
typical values and it's not clear if they are no min and max values or
if you must use the typical value exactly. To make things worse, there
is no back porch but only a combined sync and back porch length.

Unfortunately, there is not public datasheet. Therefore, here are the
relevant timings:
                 | min |  typ   | max |
-----------------+-----+--------+-----+
CLK frequency    |  -  | 25.175 |  -  |
HS period        |  -  |   800  |  -  |
HS pulse width   |  5  |    30  |  -  |
HS-DEN time      | 112 |   144  | 175 |
DEN pulse width  |  -  |   640  |  -  |
VS pulse width   |  1  |     3  |  5  |
VS-DEN time      |  -  |    35  |  -  |
VS period        |  -  |   525  |  -  |

Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231123102404.2022201-2-mwalle@kernel.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231123102404.2022201-2-mwalle@kernel.org