staging: rtl8188eu: declare internal function as static

This function is only used inside rtw_recv.c. Which is quite logical,
since it's a timer callback: it is passed as the _fn argument to
setup_timer(). So it is internal to rtw_recv.c and should be static.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Geliang Tang <geliangtang@163.com>
Cc: Jakub Sitnicki <jsitnicki@gmail.com>
Cc: Ivan Safonov <insafonov@gmail.com>
Cc: Kyle Kuffermann <kyle.kuffermann@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/core/rtw_recv.c

@@ -39,7 +39,7 @@ static u8 rtw_rfc1042_header[] = {
        0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00
 };
 
-void rtw_signal_stat_timer_hdl(unsigned long data);
+static void rtw_signal_stat_timer_hdl(unsigned long data);
 
 void _rtw_init_sta_recv_priv(struct sta_recv_priv *psta_recvpriv)
 {
@@ -2088,7 +2088,7 @@ s32 rtw_recv_entry(struct recv_frame *precvframe)
 	return ret;
 }
 
-void rtw_signal_stat_timer_hdl(unsigned long data)
+static void rtw_signal_stat_timer_hdl(unsigned long data)
 {
 	struct adapter *adapter = (struct adapter *)data;
 	struct recv_priv *recvpriv = &adapter->recvpriv;