brcmfmac: Fix double freeing in the fmac usb data path

When the brcmf_fws_process_skb() fails to get hanger slot for
queuing the skb, it tries to free the skb.
But the caller brcmf_netdev_start_xmit() of that funciton frees
the packet on error return value.
This causes the double freeing and which caused the kernel crash.
Signed-off-by: Raveendran Somu <raveendran.somu@cypress.com>
Signed-off-by: Chi-hsien Lin <chi-hsien.lin@cypress.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1585124429-97371-3-git-send-email-chi-hsien.lin@cypress.com

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

@@ -2145,8 +2145,7 @@ int brcmf_fws_process_skb(struct brcmf_if *ifp, struct sk_buff *skb)
 		brcmf_fws_enq(fws, BRCMF_FWS_SKBSTATE_DELAYED, fifo, skb);
 		brcmf_fws_schedule_deq(fws);
 	} else {
-		bphy_err(drvr, "drop skb: no hanger slot\n");
-		brcmf_txfinalize(ifp, skb, false);
+		bphy_err(drvr, "no hanger slot available\n");
 		rc = -ENOMEM;
 	}
 	brcmf_fws_unlock(fws);