dtim_period is a bss property, not a device one.
It is already handled properly in mac80211.sh
Fixes: 30c64825c7ed ("hostapd: add dtim_period, local_pwr_constraint, spectrum_mgmt_required")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry-picked from commit ddf736e543d4a214f563dc008b6fb5ee5e0d1b66)
88c43b5887