brcmfmac: drop brcmf_bus_detach and inline its code

Driver used to call brcmf_bus_detach only from one place and it already
contained a check for drvr not being NULL. We can get rid of this extra
function, call brcmf_bus_stop directly and simplify the code.
There also isn't brcmf_bus_attach function which one could expect so it
looks more consistent this way.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -1075,16 +1075,6 @@ void brcmf_bus_add_txhdrlen(struct device *dev, uint len)
 	}
 }
 
-static void brcmf_bus_detach(struct brcmf_pub *drvr)
-{
-	brcmf_dbg(TRACE, "Enter\n");
-
-	if (drvr) {
-		/* Stop the bus module */
-		brcmf_bus_stop(drvr->bus_if);
-	}
-}
-
 void brcmf_dev_reset(struct device *dev)
 {
 	struct brcmf_bus *bus_if = dev_get_drvdata(dev);
@@ -1131,7 +1121,7 @@ void brcmf_detach(struct device *dev)
 
 	brcmf_fws_deinit(drvr);
 
-	brcmf_bus_detach(drvr);
+	brcmf_bus_stop(drvr->bus_if);
 
 	brcmf_proto_detach(drvr);