nouveau: fix r535 build on 32-bit arm.

This needs the proper division macros.

Reviewed-by: Danilo Krummrich <dakr@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030012814.1208972-1-airlied@gmail.com