staging: r8188eu: make LPS_RF_ON_check static

LPS_RF_ON_check is used only in rtw_pwrctrl.c. Make it a static function.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220409163212.241122-7-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_pwrctrl.c

@@ -248,7 +248,7 @@ static bool lps_rf_on(struct adapter *adapter)
  *	-1:	Timeout
  *	-2:	Other error
  */
-s32 LPS_RF_ON_check(struct adapter *padapter, u32 delay_ms)
+static s32 LPS_RF_ON_check(struct adapter *padapter, u32 delay_ms)
 {
 	u32 start_time;
 	s32 err = 0;

drivers/staging/r8188eu/include/rtw_pwrctrl.h

@@ -104,7 +104,6 @@ int ips_leave(struct adapter *padapter);
 
 void rtw_ps_processor(struct adapter *padapter);
 
-s32 LPS_RF_ON_check(struct adapter *adapter, u32 delay_ms);
 void LPS_Enter(struct adapter *adapter);
 void LPS_Leave(struct adapter *adapter);