staging: rtl8192e: Remove unused rf_set_sens variable

The rf_set_sens variable is declared but never set, so it is always NULL.
This commit cleans up the unused rf_set_sens variable and removes the
associated code that relied on it.

Specifically, the following changes have been made:
- Removed the `range->sensitivity` assignment, which was never used.
- Removed the sensitivity level get implementation, which always returns
  an error code.
- Removed the sensitivity level set implementation, which always returns
  an error code.
- Removed the `rf_set_sens` variable.
Suggested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Signed-off-by: Yogesh Hegde <yogi.kernel@gmail.com>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/5a9767fab76b1836ea7881994ffb3593c1ab12bf.1682358035.git.yogi.kernel@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtl8192e/rtl_core.h

@@ -231,7 +231,6 @@ struct r8192_priv {
 	struct rt_stats stats;
 	struct iw_statistics			wstats;
 
-	short (*rf_set_sens)(struct net_device *dev, short sens);
 	u8 (*rf_set_chan)(struct net_device *dev, u8 ch);
 
 	struct rx_desc *rx_ring[MAX_RX_QUEUE];

drivers/staging/rtl8192e/rtl8192e/rtl_wx.c

@@ -311,10 +311,6 @@ static int _rtl92e_wx_get_range(struct net_device *dev,
 	/* ~130 Mb/s real (802.11n) */
 	range->throughput = 130 * 1000 * 1000;
 
-	if (priv->rf_set_sens != NULL)
-		/* signal level threshold range */
-		range->sensitivity = priv->max_sens;
-
 	range->max_qual.qual = 100;
 	range->max_qual.level = 0;
 	range->max_qual.noise = 0;
@@ -813,10 +809,7 @@ static int _rtl92e_wx_get_sens(struct net_device *dev,
 {
 	struct r8192_priv *priv = rtllib_priv(dev);
 
-	if (priv->rf_set_sens == NULL)
-		return -1; /* we have not this support for this radio */
-	wrqu->sens.value = priv->sens;
-	return 0;
+	return -1;
 }
 
 static int _rtl92e_wx_set_sens(struct net_device *dev,
@@ -831,15 +824,7 @@ static int _rtl92e_wx_set_sens(struct net_device *dev,
 		return 0;
 
 	mutex_lock(&priv->wx_mutex);
-	if (priv->rf_set_sens == NULL) {
-		err = -1; /* we have not this support for this radio */
-		goto exit;
-	}
-	if (priv->rf_set_sens(dev, wrqu->sens.value) == 0)
-		priv->sens = wrqu->sens.value;
-	else
-		err = -EINVAL;
-
+	err = -1;
 exit:
 	mutex_unlock(&priv->wx_mutex);