brcmfmac: remove unnecessary null pointer check

in the function brcmf_bus_start() in the exception handling a
check is made to dermine whether ifp is null, though this is not
possible. Removing the unnessary check.
Reviewed-by: Arend Van Spriel <arend.vanspriel@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Signed-off-by: Hante Meuleman <hante.meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c

@@ -1048,8 +1048,7 @@ int brcmf_bus_start(struct device *dev)
 		brcmf_fws_del_interface(ifp);
 		brcmf_fws_deinit(drvr);
 	}
-	if (ifp)
-		brcmf_net_detach(ifp->ndev, false);
+	brcmf_net_detach(ifp->ndev, false);
 	if (p2p_ifp)
 		brcmf_net_detach(p2p_ifp->ndev, false);
 	drvr->iflist[0] = NULL;