bcm63xx: fix compilation with kmod-ohci enabled with 3.6

Fixes the following error:

drivers/usb/host/ohci-bcm63xx.c: In function 'ohci_bcm63xx_start':
drivers/usb/host/ohci-bcm63xx.c:33:3: error: implicit declaration of function 'err' [-Werror=implicit-function-declaration]

Reported-by: Álvaro Fernández Rojas <noltari@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34138 3c298f89-4303-0410-b956-a3cf2f4a3e73