ath9k: make MAC sample statistics optional

They're more expensive than some of the other debug options and only used
in very rare situations, so it sometimes makes sense to disable them while
leaving in debugfs support.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
4 files changed