brcmfmac: remove unnecessary curly braces in dhd_attach()

Stumbled into a curly braces used for if statement with only
one conditional statement. Removing them.
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@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/dhd_linux.c

@@ -890,9 +890,8 @@ void brcmf_detach(struct device *dev)
 
 	brcmf_bus_detach(drvr);
 
-	if (drvr->prot) {
+	if (drvr->prot)
 		brcmf_proto_detach(drvr);
-	}
 
 	brcmf_debugfs_detach(drvr);
 	bus_if->drvr = NULL;