drm/panel-edp: Fix variable typo when saving hpd absent delay from DT

The value read from the "hpd-absent-delay-ms" property in DT was being
saved to the wrong variable, overriding the hpd_reliable delay. Fix the
typo.

Fixes: 5540cf8f

 ("drm/panel-edp: Implement generic "edp-panel"s probed by EDID")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220719203857.1488831-4-nfraprado@collabora.com