ath9k_hw: prevent writes to const data on AR9160

commit 9bbb8168ed3d8b946f9c1901a63a675012de88f2 upstream.

Duplicate the data for iniAddac early on, to avoid having to do redundant
memcpy calls later. While we're at it, make AR5416 < v2.2 use the same
codepath. Fixes a reported crash on x86.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Reported-by: Magnus Määttä <magnus.maatta@logica.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>