ath5k: Don't call reset on config_interface

 * We call reset too often and this can result various PHY problems.
  On config_interface we don't need to reset the whole device.

  TODO: Create a function hw_fast_reset that only resets the PCU
  (tx/rx stuff) and not the whole device so that we can use this for
  stuck beacons etc.

Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>

Signed-off-by: John W. Linville <linville@tuxdriver.com>