qcacld-3.0: Fix -Wmissing-prototypes in wlan_hdd_tsf

We want to enable the compiler's -Wmissing-prototypes switch, but
there is existing code that is generating warnings. Fix all warnings
in wlan_hdd_tsf.

Change-Id: I37e98814da218d9322a8d3ac05a0e19523859281
CRs-Fixed: 1074336
diff --git a/core/hdd/src/wlan_hdd_tsf.c b/core/hdd/src/wlan_hdd_tsf.c
index e230925..00ba66a 100644
--- a/core/hdd/src/wlan_hdd_tsf.c
+++ b/core/hdd/src/wlan_hdd_tsf.c
@@ -30,6 +30,7 @@
  */
 
 #include "wlan_hdd_main.h"
+#include "wlan_hdd_tsf.h"
 #include "wma_api.h"
 
 static struct completion tsf_sync_get_completion_evt;
@@ -110,13 +111,13 @@
  * Return: TSF_RETURN on Success, TSF_RESET_GPIO_FAIL on failure
  */
 #ifdef QCA_WIFI_3_0
-int hdd_tsf_reset_gpio(struct hdd_adapter_s *adapter)
+static int hdd_tsf_reset_gpio(struct hdd_adapter_s *adapter)
 {
 	/* No GPIO Host timer sync for integrated WIFI Device */
 	return TSF_RETURN;
 }
 #else
-int hdd_tsf_reset_gpio(struct hdd_adapter_s *adapter)
+static int hdd_tsf_reset_gpio(struct hdd_adapter_s *adapter)
 {
 	int ret;
 	ret = wma_cli_set_command((int)adapter->sessionId,