drm/panel-edp: hpd_reliable shouldn't be subtraced from hpd_absent

Now that the delays are named / described with eDP-centric names, it
becomes clear that we should really specify the "hpd_reliable" and
"hpd_absent" separately without taking the other into account. Let's
fix it.

This should be a no-op change and just adjust how we specify
things. The actual delays should be the same before and after for the
one panel that currently species both "hpd_reliable" and "hpd_absent".

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210914132020.v5.12.I2522235fca3aa6790ede0bf22a93d79a1f694e6b@changeid