mac80211: fix smatch complains

mlme.c
	l.757 ieee80211_dynamic_ps_enable_work(11)
	variable dereferenced before check 'sdata'

mesh_pathtbl.c
	l.650 mesh_path_del(20) double lock 'bottom_half'
	l.663 mesh_path_del(33) double unlock 'bottom_half'

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>