tests: Fix dbus_interface to restore P2P channel list to default

tests: Fix dbus_interface to restore P2P channel list to default

It was possible for the dbus_interface test case to leave the P2P
channel lists with 5 GHz channels enabled due to the special driver=none
case. This could make the following P2P test case fail due to selecting
an unexpected channel. Fix this by forcing P2P channel list update at
the end of the dbus_interface test case.

This was triggering with the following hwsim test case sequence:
dbus_interface p2ps_connect_adv_go_p2ps_method_group_iface.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>