drm/i915: Fix TLB-Invalidation seqno store

When getting the next gt's seqno to be stored into an
objects mm.tlb[gt_id] array, fix the retrieval code
to get it from the correct gt instead of the same one.

Fixes: d6c531ab

 ("drm/i915: Invalidate the TLBs on each GT")
Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230814182449.1060747-1-alan.previn.teres.alexis@intel.com
(cherry picked from commit 90b8ad13

)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>