iris: Don't call SET_TILING for dmabuf imports

iris: Don't call SET_TILING for dmabuf imports

Calling SET_TILING on a DMA buffer with the gen12 CCS modifier can fail
unnecessarily. The main surface in the BO is Y-tiled, but the CCS portion is
linear and can have a stride that's not a multiple of 128B. Because SET_TILING
is called on the CCS plane with I915_TILING_Y, the ioctl will sometimes reject
the stride.

SET_TILING was originally used in b6d45e7f748e9ff7e198391f5ce5d1253101fedb to
fix an assertion failure in iris_resource_from_handle. Assigning the BO's
tiling_mode field is sufficient to avoid the failure.

Fixes: c19492bcdb9 ("iris: Handle importing aux-enabled surfaces on TGL")
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6296>