wl12xx: Revert "wl12xx: disable auto-arp"

This reverts commit e5e2f24b.

The encryption consideration on auto-arp configuration,
along with a fw fix, seem to resolve the crashes that
occured when auto-arp was enabled, so we can re-enable it now.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/wl12xx/main.c

@@ -3862,7 +3862,8 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
 			}
 
 			ret = wl1271_acx_arp_ip_filter(wl, wlvif,
-				ACX_ARP_FILTER_ARP_FILTERING,
+				(ACX_ARP_FILTER_ARP_FILTERING |
+				 ACX_ARP_FILTER_AUTO_ARP),
 				addr);
 		} else {
 			wlvif->ip_addr = 0;