ath5k: Correct channel setting for AR2317 chip

Correct channel setting function must be used for AR2317.
When I tested ahb patch on bullet2 all seemed to work fine,
but it couldn't connect another host (using ibss for example).
During an analysis I observed that it's transmitting on another
channel. I looked into madwifi code and understood that
the problem is in channel setting function. So atheros RF2317 not
fully handled in the current ath5k version and must be patched.

Signed-off-by: Nikolay Ledovskikh <nledovskikh@gmail.com>
Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>