scons: fix SPIR-V -> NIR build

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Tested-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Fixes: 18f9fc919e1 ('spirv: add and use a generator id enum')
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7096>
1 file changed