ath: Add and use pr_fmt, convert printks to pr_<level>

Use a more current logging style.
Make sure all output is prefixed appropriately.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/sysfs.c b/drivers/net/wireless/ath/ath5k/sysfs.c
index 9364da7..04cf0ca 100644
--- a/drivers/net/wireless/ath/ath5k/sysfs.c
+++ b/drivers/net/wireless/ath/ath5k/sysfs.c
@@ -1,3 +1,5 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/device.h>
 #include <linux/pci.h>