ath9k: Fix AR955x RX sensitivity

AR955x has problems with RX sensitivity in 2G. This patch
adds a routine to select range_osdac dynamically on a
per-chain basis to address this issue.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/ath/ath9k/ar9003_calib.c
Simple merge

diff --cc drivers/net/wireless/ath/ath9k/ar9003_phy.h
Simple merge