anv: Validate the list of BOs from the block pool.

anv: Validate the list of BOs from the block pool.

We now have multiple BOs in the block pool, but sometimes we still
reference only the first one in some instructions, and use relative
offsets in others. So we must be sure to add all the BOs from the block
pool to the validation list when submitting commands.

v2:
   - Don't add block pool BOs to the dependency list right before
   execbuf (Jason)
   - Call anv_execbuf_add_bo() to each BO in the block pools (Jason)
   - Use anv_execbuf_add_bo_set() to add surface state dependencies to
   execbuf.

v3:
   - Add comment to the non-softpin case (Jason).

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>