Revert "ath9k_hw: Updated AR9003 tx gain table for 5GHz"

This reverts commit a240dc7b3c7463bd60cf0a9b2a90f52f78aae0fd.

This commit is reducing tx power by at least 10 db on some devices,
e.g. the Buffalo WZR-HP-G450H.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: stable@vger.kernel.org
Cc: rmanohar@qca.qualcomm.com
Signed-off-by: John W. Linville <linville@tuxdriver.com>