freedreno: Stop treating UBO 0 specially in UBO uploading.

freedreno: Stop treating UBO 0 specially in UBO uploading.

ir3_nir_analyze_ubo_ranges() has already told us how much of cb0 we
need to upload (all of it, since it will lower indirect UBO 0 accesses
from load_ubo back to indirection on the constant buffer).

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>