brcmfmac: fix sdio sending of large buffers.

the function brcmf_sdiod_ramrw is supposed to be able to send
large blobs of data. However inside the loop the skb->len field
did not correctly get reset each round. As a result only small
blobs could be sent. This patch fixes this problem.
Reviewed-by: NArend Van Spriel <arend@broadcom.com>
Reviewed-by: NFranky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: NPieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: NDaniel (Deognyoun) Kim <dekim@broadcom.com>
Signed-off-by: NHante Meuleman <meuleman@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c

@@ -826,7 +826,7 @@ brcmf_sdiod_ramrw(struct brcmf_sdio_dev *sdiodev, bool write, u32 address,
 		}
 		if (!write)
 			memcpy(data, pkt->data, dsize);
-		skb_trim(pkt, dsize);
+		skb_trim(pkt, 0);
 
 		/* Adjust for next transfer (if any) */
 		size -= dsize;