drm/panel: st7703: Pick different reset sequence

Switching to a different reset sequence, enabling IOVCC before enabling
VCC.

There also needs to be a delay after enabling the supplies and before
deasserting the reset. The datasheet specifies 1ms after the supplies
reach the required voltage. Use 10-20ms to also give the power supplies
some time to reach the required voltage, too.

This fixes intermittent panel initialization failures and screen
corruption during resume from sleep on panel xingbangda,xbd599 (e.g.
used in PinePhone).

Signed-off-by: Ondrej Jirman <megi@xff.cz>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
Reported-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Tested-by: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230211171748.36692-2-frank@oltmanns.dev