brcmfmac: get rid of extern keyword in wl_cfg80211.h

The function declarations in wl_cfg80211.h used the extern keyword
but it is redundant as that is implicit so they were removed.
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@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.h

@@ -497,15 +497,15 @@ brcmf_cfg80211_connect_info *cfg_to_conn(struct brcmf_cfg80211_priv *cfg)
 	return &cfg->conn_info;
 }
 
-extern struct brcmf_cfg80211_dev *brcmf_cfg80211_attach(struct net_device *ndev,
-							struct device *busdev,
-							struct brcmf_pub *drvr);
-extern void brcmf_cfg80211_detach(struct brcmf_cfg80211_dev *cfg);
+struct brcmf_cfg80211_dev *brcmf_cfg80211_attach(struct net_device *ndev,
+						 struct device *busdev,
+						 struct brcmf_pub *drvr);
+void brcmf_cfg80211_detach(struct brcmf_cfg80211_dev *cfg);
 
 /* event handler from dongle */
-extern void brcmf_cfg80211_event(struct net_device *ndev,
-				 const struct brcmf_event_msg *e, void *data);
-extern s32 brcmf_cfg80211_up(struct brcmf_cfg80211_dev *cfg_dev);
-extern s32 brcmf_cfg80211_down(struct brcmf_cfg80211_dev *cfg_dev);
+void brcmf_cfg80211_event(struct net_device *ndev,
+			  const struct brcmf_event_msg *e, void *data);
+s32 brcmf_cfg80211_up(struct brcmf_cfg80211_dev *cfg_dev);
+s32 brcmf_cfg80211_down(struct brcmf_cfg80211_dev *cfg_dev);
 
 #endif				/* _wl_cfg80211_h_ */