ath9k: separate debugfs support from CONFIG_ATH_DEBUG

In my setups, ath9k's debugfs files are most of the time much more
useful than the messages generated by enabling CONFIG_ATH_DEBUG along
with the right debug flags.
Since CONFIG_ATH_DEBUG comes with a noticeable overhead on embedded
systems, this patch makes it possible to use the debugfs files without
that option.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/Makefile b/drivers/net/wireless/ath/ath9k/Makefile
index e53f9680..4985b2b 100644
--- a/drivers/net/wireless/ath/ath9k/Makefile
+++ b/drivers/net/wireless/ath/ath9k/Makefile
@@ -7,7 +7,7 @@
 
 ath9k-$(CONFIG_PCI) += pci.o
 ath9k-$(CONFIG_ATHEROS_AR71XX) += ahb.o
-ath9k-$(CONFIG_ATH9K_DEBUG) += debug.o
+ath9k-$(CONFIG_ATH9K_DEBUGFS) += debug.o
 
 obj-$(CONFIG_ATH9K) += ath9k.o