libertas: fix data packet size errors

I wondered about junk bytes at the end when using "lbsdebug +hex +host"
until I noticed that firmware for the CF card sends my extranous bytes.
It says "I have 20 bytes", I take 20 bytes, but the last 8 bytes of this
are just data junk.

Also, in the new lbs_cmd() where was a size miscalulation
that made itself clear after fixing this bug.

Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/if_cs.c b/drivers/net/wireless/libertas/if_cs.c
index 54b1ba3..8508260 100644
--- a/drivers/net/wireless/libertas/if_cs.c
+++ b/drivers/net/wireless/libertas/if_cs.c
@@ -373,6 +373,9 @@
 	if (*len & 1)
 		data[*len-1] = if_cs_read8(priv->card, IF_CS_C_CMD);
 
+	/* This is a workaround for a firmware that reports too much
+	 * bytes */
+	*len -= 8;
 	ret = 0;
 out:
 	lbs_deb_leave_args(LBS_DEB_CS, "ret %d, len %d", ret, *len);