cloud-setup: avoid accidental cast into a smaller type

This resulted in what looked like more significant bits of GType pointer
sometimes falling off the cliff, presumably because of a cast to
NMDeviceType enum (that probably ends up actually being a char).

This was silent enough to not emit compiler warnings and only occurring
with some very rare situations (needs GCC with LTO and some of the
optimization flags used by Fedora 41).

Fixes: cf6af54ffa ('cloud-setup: allow VETH along with ETHERNET too')
Fixes: 6ff4b9e57c ('cloud-setup: create VLANs for multiple VNICs on OCI')

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/2119

src/nm-cloud-setup/main.c

@@ -833,7 +833,7 @@ _oci_config_vnic_dev(SigTermData                          *sigterm_data,
                      const NMCSProviderGetConfigIfaceData *config_data,
                      NMClient                             *nmc,
                      const NMCSProviderGetConfigResult    *result,
-                     NMDeviceType                          device_type,
+                     const GType                           device_type,
                      const char                           *connection_type,
                      const char                           *parent_hwaddr)
 {