v3dv: lower usubborrow and uaddcarry

For some reason our backend compiler doesn't have an implementation for
usubborrow, only for uaddcarry. We could add it, however, the existing
uaddcarry implementation also seems to fail some of the CTS tests,
which pass if we lower.

Fixes:
dEQP-VK.glsl.builtin.function.integer.uaddcarry.*
dEQP-VK.glsl.builtin.function.integer.usubborrow.*

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
1 file changed