i965: Drop brw_bo_alloc in ARB_indirect_parameters implementation.

i965: Drop brw_bo_alloc in ARB_indirect_parameters implementation.

The original implementation allocated a new BO here, but we decided to
switch to intel_upload_space, which returns a reference to the current
upload BO.  We accidentally kept the brw_bo_alloc, even though it's no
longer necessary - intel_upload_space will immediately unreference it,
causing us to allocate and immediately free a buffer.

Reviewed-by: Plamena Manolova <plamena.manolova@intel.com>