iwlwifi: fix AMSDU Rx after paged Rx patch

Previous patch "use paged Rx" broke AMSDU Rx functionality. If an AP
sends out A-MSDU packets the station will crash.  Fix it by linearizing
skbuff for AMSDU packet before handing it to mac80211 since mac80211
doesn't support paged skbuff.

This fixes http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2155

Reported-by: Norbert Preining <preining@logic.at>
Signed-off-by: Shanyu Zhao <shanyu.zhao@intel.com>
Acked-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-rx.c

@@ -928,7 +928,10 @@ static void iwl_pass_packet_to_mac80211(struct iwl_priv *priv,
 	if (ieee80211_is_mgmt(fc) ||
 	    ieee80211_has_protected(fc) ||
 	    ieee80211_has_morefrags(fc) ||
-	    le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG)
+	    le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG ||
+	    (ieee80211_is_data_qos(fc) &&
+	     *ieee80211_get_qos_ctl(hdr) &
+	     IEEE80211_QOS_CONTROL_A_MSDU_PRESENT))
 		ret = skb_linearize(skb);
 	else
 		ret = __pskb_pull_tail(skb, min_t(u16, IWL_LINK_HDR_MAX, len)) ?