v3d/tex: use TMUSLOD register if possible

v3d/tex: use TMUSLOD register if possible

TMUSLOD register is the same that TMUS but having the same effect that
setting disable_autolod on the TMU configuration parameter 2.

So using that register is potentially more efficient, as in several
cases we would be able to skip writing P2.

One case where we can't use it is for texture cube maps, as we need to
use TMUSCM.

v2: don't put a comment in the middle of the conditions (Iago)

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4962>