ath9k: add struct ath_spec_scan_priv

and move rfs_chan_spec_scan to this struct. We will need it
for common spectral scan code.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/ath/ath9k/ath9k.h
Simple merge

diff --cc drivers/net/wireless/ath/ath9k/spectral.c
Simple merge

diff --cc drivers/net/wireless/ath/ath9k/spectral.h
Simple merge