aco: Fix NGG GS assert failure from the WG scan.

There was a temp which was defined in a branch but used outside,
without a phi.

Fixes: 62b5012ec35358a7c109746bfe1da33ca1b04f24
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7817>
(cherry picked from commit 94f8cb29ee7c615e74b4a85e14ac9e22c5dd7f2a)
2 files changed