Simple compile warning fix. (against 2.6.23-git12)

Thanks,
Badari

vortex_up() should initialize 'err' for a successful return.

drivers/net/3c59x.c: In function `vortex_up':
drivers/net/3c59x.c:1494: warning: `err' might be used uninitialized in this function
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>