UPSTREAM: drm/i915: Allow bigjoiner for MST

We need bigjoiner support with MST functionality
for MST monitor resolutions > 5K to work.
Adding support for the same.

v2: Addressed review comments from Jani.
Revert rejection of MST bigjoiner modes and add
functionality

v3: Fixed pipe_mismatch WARN for mst_master_transcoder
Credits-to: Manasi Navare <navaremanasi@chromium.org>

v4: Utilize intel_crtc_joined_pipe_mask() also for handling
    bigjoiner slave pipes for MST case(Stan)
[v5: vsyrjala: chunked the modeset squence stuff out,
               removed bogus mst master transcoder hack,
	       keep mgr_lock near the full_pbn check]
[v6: vsyrjala: Calculate DSC slices correctly for bigjoiner (Imre)]

Reviewed-by: Manasi Navare <navaremanasi@chromium.org>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
Co-developed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240409163502.29633-7-ville.syrjala@linux.intel.com


(cherry picked from commit 578ff984)

BUG=b:308455498
TEST=Verify Asus PG32UQXR 4K160 mode on Rex using Big Joiner

Change-Id: Ic0ad33220bf9b500389cf489bf15c702756c0d9c
Signed-off-by: Rakshith M O <rakshith.m.o@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/5802870


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