staging: brcm80211: remove unnecessary null check

kfree(NULL) is safe, and the rest of the cleanup should be done regardless
to make sure the state is consistent.
Signed-off-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmfmac/dhd_sdio.c

@@ -5567,11 +5567,9 @@ static void dhdsdio_release_malloc(dhd_bus_t *bus)
 	if (bus->dhd && bus->dhd->dongle_reset)
 		return;
 
-	if (bus->rxbuf) {
 	kfree(bus->rxbuf);
 	bus->rxctl = bus->rxbuf = NULL;
 	bus->rxlen = 0;
-	}
 
 	kfree(bus->databuf);
 	bus->databuf = NULL;