UPSTREAM: drm/i915/adlp: Add MST short HBlank WA (Wa_14014143976)

Add a workaround to fix BS jitter issues on MST links if the HBLANK
period is less than 1 MTP. The WA applies only to UHBR rates while on
non-UHBR the specification requires disabling it explicitly - presumedly
because the register's reset value has the WA enabled.

Bspec: 50050, 55424

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/20240129175533.904590-3-imre.deak@intel.com


(cherry picked from commit 1af52d05)

BUG=b:332903004, b:322223603
TEST=Verify Dell U3224KB 6k mode on Rex using UHBR, MST encoder, Big
     Joiner, and DSC

Change-Id: Icd467661ab57a9d9ddd8ae24854e71f4bbbfa4af
Signed-off-by: Rakshith M O <rakshith.m.o@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/5802877


Reviewed-by: Manasi Navare <navaremanasi@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Hubert Mazur <hmazur@google.com>