MLK-18675-10 brcmfmac: calling skb_orphan before sending skb to SDIO bus

MLK-18675-10 brcmfmac: calling skb_orphan before sending skb to SDIO bus

Linux 3.6 introduces TSQ which has a per socket threshold for TCP Tx
packet to reduce latency. In fcmode 1/2, host driver enqueues skb in
hanger and TCP doesn't push new skb frees until host frees the skb when
receiving fwstatus event. So using skb_orphan before sending skb to bus
will make the skb removing the ownership of socket. With this patch, we
got better throughput in fcmode 1/2.

Tested 43455 TCP throughput in 20 MHz bandwidth with/without this patch.
fcmode 0: 59.5 / 59.6 (Mbps)
fcmode 1: 59.3 / 23.4 (Mbps)
fcmode 2: 59.6 / 21.5 (Mbps)

Signed-off-by: Wright Feng <wright.feng@cypress.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>