staging: r8188eu: Fix sparse warning in core/rtw_pwrctrl.c

Sparse reports the following:

  CHECK   drivers/staging/rtl8188eu/core/rtw_pwrctrl.c
drivers/staging/rtl8188eu/core/rtw_pwrctrl.c:525:6: warning: symbol 'rtw_free_pwrctrl_priv' was not declared. Should it be static?

That routine is not used and has been deleted.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/core/rtw_pwrctrl.c

@@ -522,10 +522,6 @@ _func_enter_;
 _func_exit_;
 }
 
-void rtw_free_pwrctrl_priv(struct adapter *adapter)
-{
-}
-
 u8 rtw_interface_ps_func(struct adapter *padapter, enum hal_intf_ps_func efunc_id, u8 *val)
 {
 	u8 bResult = true;