Darn this gave me some headaches bc they changed things again 
Better put the IP on the bridge interface like below.
In "/etc/network/interfaces":
allow-hotplug eth0
iface eth0 inet manual
allow-hotplug wlan0
iface wlan0 inet manual
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
wpa-ssid <YOUR_SSID_NAME>
wpa-psk <PASSWORD>
auto br0
iface br0 inet manual
bridge_ports eth0 wlan0
In "/etc/dhcpcd.conf":
interface eth0
nodhcp
nodhcp6
interface wlan0
nodhcp
nodhcp6
interface br0
static ip_address=192.168.178.40/24
static routers=192.168.178.1
static domain_name_servers=127.0.0.1
Let me know if works ?
Ps. forget hot-plug without real STP.