drm/i915: Reuse <platform>_hotplug_mask() in .hpd_detection_setup()

Replace the hardcoded masks with just a loop over all hpd
pins using the <platform>_hotplug_mask() functions.

v2: Deal with mtp

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com> #v1
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230417131728.7705-5-ville.syrjala@linux.intel.com