driver core:fix duplicate removing driver link in __device_release_driver

In __device_release_driver(),driver_sysfs_remove() has removed the
driver link under device dir in sysfs, but sysfs_remove_link() is
called again to do such thing. Remove the duplicate call to
sys_remove_link().

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>