ath5k: Disable ANI during reset

 * Stop ANI durring reset to prevent false PHY error reports

Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>