drm/vc4: hdmi: Fix outdated function name in comment

drm/vc4: hdmi: Fix outdated function name in comment

A comment introduced by commit 6bed2ea3cb38 ("drm/vc4: hdmi: Reset link
on hotplug") mentions a drm_atomic_helper_connector_hdmi_reset_link()
function that was part of the earlier versions but got moved internally
and is now named vc4_hdmi_reset_link(). Let's fix the function name.

Fixes: 6bed2ea3cb38 ("drm/vc4: hdmi: Reset link on hotplug")
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20221024093634.118190-2-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>