iris: Add an alignment parameter to iris_bo_alloc()

This is rarely useful, but after the next patch removes tiling tracking,
this would literally be the only difference between iris_bo_alloc and
iris_bo_alloc_tiled, so we may as well add it.

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11169>
10 files changed