mac80211: add mesh_param support

mac80211: add mesh_param support

This patch add mesh_param support in mac80211.sh
It suppose that this patch http://patchwork.openwrt.org/patch/3540/ is applied (add HT support for mesh)

Tested with rspro(ar9280)/wr1043nd, BB r36211
see also this http://lists.open80211s.org/pipermail/devel/2012-June/003352.html
(mesh_hwmp_rootmode 1 & mesh_gate_announcements 1
=> mesh_hwmp_rootmode 4 & mesh_gate_announcements 1)

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36640 3c298f89-4303-0410-b956-a3cf2f4a3e73