drm/msm: make sure last_fence is always updated

drm/msm: make sure last_fence is always updated

Update last_fence in the vm-bind path instead of kernel managed path.

last_fence is used to wait for work to finish in vm_bind contexts but not
used for kernel managed contexts.

This fixes a bug where last_fence is not waited on context close leading
to faults as resources are freed while in use.

Fixes: 92395af63a99 ("drm/msm: Add VM_BIND submitqueue")
Signed-off-by: Anna Maniscalco <anna.maniscalco2000@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/680080/
Message-ID: <20251011-close_fence_wait_fix-v3-1-5134787755ff@gmail.com>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>