wifi: mac80211: fix ieee80211_link_set_associated() type

The return type here should be u64 for the flags, even
if it doesn't matter right now because it doesn't return
any flags that don't fit into u32.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230301115906.d67ccae57d60.Ia4768e547ba8b1deb2b84ce3bbfbe216d5bfff6a@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>