Staging: rtl8188eu: rtw_pwrctrl: fixed checkpatch warning.

WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt
Signed-off-by: Surya Seetharaman <suryaseetharaman.9@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/core/rtw_pwrctrl.c

@@ -577,7 +577,7 @@ int _rtw_pwr_wakeup(struct adapter *padapter, u32 ips_deffer_ms, const char *cal
 	if (pwrpriv->ps_processing) {
 		DBG_88E("%s wait ps_processing...\n", __func__);
 		while (pwrpriv->ps_processing && rtw_get_passing_time_ms(start) <= 3000)
-			msleep(10);
+			usleep_range(1000, 3000);
 		if (pwrpriv->ps_processing)
 			DBG_88E("%s wait ps_processing timeout\n", __func__);
 		else