staging: brcm80211: use fragment number provided in transmit frame

In the transmit path the field seq_ctrl is filled in, but the fragment
number was not properly determined.
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmsmac/main.c

@@ -7100,7 +7100,7 @@ brcms_c_d11hdrs_mac80211(struct brcms_c_info *wlc, struct ieee80211_hw *hw,
 				scb->seqnum[p->priority]++;
 
 			/* extract fragment number from frame first */
-			seq = le16_to_cpu(seq) & FRAGNUM_MASK;
+			seq = le16_to_cpu(h->seq_ctrl) & FRAGNUM_MASK;
 			seq |= (scb->seqnum[p->priority] << SEQNUM_SHIFT);
 			h->seq_ctrl = cpu_to_le16(seq);