kernel: fix dependecy of kmod-ieee802154_6lowpan

This module also depends on kmod-ieee802154

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46407 3c298f89-4303-0410-b956-a3cf2f4a3e73