ath6kl: Fix compilation error while compiling w/o debug

drivers/net/wireless/ath/ath6kl/htc_hif.o:
In function `ath6kl_debug_fwlog_event':
drivers/net/wireless/ath/ath6kl/debug.h:109:
multiple definition of `ath6kl_debug_fwlog_event'
drivers/net/wireless/ath/ath6kl/debug.o:
drivers/net/wireless/ath/ath6kl/debug.h:109: first defined here
drivers/net/wireless/ath/ath6kl/htc_hif.o:
In function `ath6kl_debug_cleanup':
drivers/net/wireless/ath/ath6kl/debug.h:118:
multiple definition of `ath6kl_debug_cleanup'
drivers/net/wireless/ath/ath6kl/debug.o:
drivers/net/wireless/ath/ath6kl/debug.h:118: first defined here

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath6kl/debug.h b/drivers/net/wireless/ath/ath6kl/debug.h
index f0d6471..89bf8e1 100644
--- a/drivers/net/wireless/ath/ath6kl/debug.h
+++ b/drivers/net/wireless/ath/ath6kl/debug.h
@@ -105,7 +105,8 @@
 {
 }
 
-void ath6kl_debug_fwlog_event(struct ath6kl *ar, const void *buf, size_t len)
+static inline void ath6kl_debug_fwlog_event(struct ath6kl *ar,
+					    const void *buf, size_t len)
 {
 }
 
@@ -114,7 +115,7 @@
 	return 0;
 }
 
-void ath6kl_debug_cleanup(struct ath6kl *ar)
+static inline void ath6kl_debug_cleanup(struct ath6kl *ar)
 {
 }