staging: rtl8192e: Remove unsupported mode IW_MODE_ADHOC

Remove unsupported mode IW_MODE_ADHOC because this mode is only partially
coded in the driver.

rtllib_rx_mgt() can only handle probe requests in IW_MODE_ADHOC and no
authentication or association frames.
Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/20230827132704.GA12506@matrix-ESPRIMO-P710Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtllib_softmac_wx.c

@@ -258,7 +258,6 @@ int rtllib_wx_set_mode(struct rtllib_device *ieee, struct iw_request_info *a,
 	mutex_lock(&ieee->wx_mutex);
 	switch (wrqu->mode) {
 	case IW_MODE_MONITOR:
-	case IW_MODE_ADHOC:
 	case IW_MODE_INFRA:
 		break;
 	case IW_MODE_AUTO: