agx: Handle 64-bit moves

agx: Handle 64-bit moves

lower_resinfo generates some 64-bit math, so we need to handle it. Even
though we don't have native 64-bit moves, it's convenient to pretend we
do to avoid special cases in the IR. In particular, modelling 64-bit
mov_imm in the IR means our existing small constant propagation code
works, with zero-extension from 8->64.

Fixes dEQP-GLES3.functional.texture.units.2_units.only_2d_array.*

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18813>