brcmfmac: add brcmf_p2p_detach() call in brcmf_cfg80211_detach()

The function brcmf_p2p_detach() was only called in error flow of the
brcmf_cfg80211_attach() routine, but it also needs to be called
upon brcmf_cfg80211_detach().

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c

@@ -5682,6 +5682,7 @@ void brcmf_cfg80211_detach(struct brcmf_cfg80211_info *cfg)
 	WARN_ON(!list_empty(&cfg->vif_list));
 	wiphy_unregister(cfg->wiphy);
 	brcmf_btcoex_detach(cfg);
+	brcmf_p2p_detach(&cfg->p2p);
 	wl_deinit_priv(cfg);
 	brcmf_free_wiphy(cfg->wiphy);
 }