brcmsmac: avoid 512 byte stack variable

Dynamically allocate the probe response template which
avoids potential stack corruption. Observed with smatch:

drivers/net/wireless/brcm80211/brcmsmac/main.c:7412 brcms_c_bss_update_probe_resp()
 warn: 'prb_resp' puts 512 bytes on stack

Cc: Brett Rudley <brudley@broadcom.com>
Cc: Arend van Spriel <arend@broadcom.com>
Cc: "Franky (Zhenhui) Lin" <frankyl@broadcom.com>
Cc: Hante Meuleman <meuleman@broadcom.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-wireless@vger.kernel.org
Cc: brcm80211-dev-list@broadcom.com
Cc: netdev@vger.kernel.org
Signed-off-by: NTim Gardner <tim.gardner@canonical.com>
Acked-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmsmac/main.c

@@ -7405,9 +7405,13 @@ brcms_c_bss_update_probe_resp(struct brcms_c_info *wlc,
 			      struct brcms_bss_cfg *cfg,
 			      bool suspend)
 {
-	u16 prb_resp[BCN_TMPL_LEN / 2];
+	u16 *prb_resp;
 	int len = BCN_TMPL_LEN;
 
+	prb_resp = kmalloc(BCN_TMPL_LEN, GFP_ATOMIC);
+	if (!prb_resp)
+		return;
+
 	/*
 	 * write the probe response to hardware, or save in
 	 * the config structure
@@ -7441,6 +7445,8 @@ brcms_c_bss_update_probe_resp(struct brcms_c_info *wlc,
 
 	if (suspend)
 		brcms_c_enable_mac(wlc);
+
+	kfree(prb_resp);
 }
 
 void brcms_c_update_probe_resp(struct brcms_c_info *wlc, bool suspend)