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

commit 73b26df5 upstream.

This reverts commit a240dc7b.

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: rmanohar@qca.qualcomm.com
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>