ath5k: Rename ath5k_copy_channels

Rename ath5k_copy_channels() to ath5k_setup_channels() - nothing is copied
here.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Acked-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>