lantiq: fix ath_pci_fixup hang on bridged devices

lantiq: fix ath_pci_fixup hang on bridged devices

Port of r41856.

In contrast to the brcm63xx target, it isn't sufficient to enable/disable
the bridge. The device needs to be enabled/disabled to fix the hang. The
bridge will be automatically enabled by the time the connected device is
enabled.

Fixes boot on TD-W8980.

Signed-off-by: Mathias Kresin <openwrt@kresin.me>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@47129 3c298f89-4303-0410-b956-a3cf2f4a3e73