mac80211: always have ieee80211_sta_restart()

When CONFIG_PM isn't defined we don't have the function
ieee80211_sta_restart() compiled in, but we always need
it now for firmware restart. Move it out of the ifdef.

Fixes: 7d352ccf ("mac80211: Add support to trigger sta disconnect on hardware restart")
Link: https://lore.kernel.org/r/20220312221957.1fa96c72db51.I8ecaa5f9402fede0272161e0531ab930b97fba3e@changeid


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