MAINTAINERS: change Kalle as ath.ko maintainer

Luis hasn't worked on ath.ko for some time now.
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

MAINTAINERS

@@ -2330,7 +2330,7 @@ F:	drivers/gpio/gpio-ath79.c
 F:	Documentation/devicetree/bindings/gpio/gpio-ath79.txt
 
 ATHEROS ATH GENERIC UTILITIES
-M:	"Luis R. Rodriguez" <mcgrof@do-not-panic.com>
+M:	Kalle Valo <kvalo@codeaurora.org>
 L:	linux-wireless@vger.kernel.org
 S:	Supported
 F:	drivers/net/wireless/ath/*