drm/i915/dp: Fix DSC state HW readout for SST connectors

Commit a62e1459 ("drm/i915/dp: Fix connector DSC HW state readout")
moved the DSC HW state readout to a connector specific hook, however
only added the hook for DP MST connectors, not for DP SST ones. Fix
adding the hook for SST connectors as well.

This fixes the following warn on platforms where BIOS enables DSC:

[   66.208601] i915 0000:00:02.0: drm_WARN_ON(!connector->dp.dsc_decompression_aux || !connector->dp.dsc_decompression_enabled)
...
[   66.209024] RIP: 0010:intel_dp_sink_disable_decompression+0x76/0x110 [i915]
...
[   66.209333]  ? intel_dp_sink_disable_decompression+0x76/0x110 [i915]
...
[   66.210068]  intel_disable_ddi+0x135/0x1d0 [i915]
[   66.210302]  intel_encoders_disable+0x9b/0xc0 [i915]
[   66.210565]  hsw_crtc_disable+0x153/0x170 [i915]
[   66.210823]  intel_old_crtc_state_disables+0x52/0xb0 [i915]
[   66.211107]  intel_atomic_commit_tail+0x5cf/0x1330 [i915]
[   66.211366]  intel_atomic_commit+0x39d/0x3f0 [i915]
[   66.211612]  ? intel_atomic_commit+0x39d/0x3f0 [i915]
[   66.211872]  drm_atomic_commit+0x9d/0xd0 [drm]
[   66.211921]  ? __pfx___drm_printfn_info+0x10/0x10 [drm]
[   66.211975]  intel_initial_commit+0x1a8/0x260 [i915]
[   66.212234]  intel_display_driver_probe+0x2a/0x80 [i915]
[   66.212479]  i915_driver_probe+0x7c6/0xc60 [i915]
[   66.212664]  ? drm_privacy_screen_get+0x168/0x190 [drm]
[   66.212711]  i915_pci_probe+0xe2/0x1c0 [i915]

Fixes: a62e1459 ("drm/i915/dp: Fix connector DSC HW state readout")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10410


Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240311145626.2454923-1-imre.deak@intel.com