staging: rtl8192e: Remove unnecessary code

kfree on NULL pointer is a no-op.

This used the following semantic patch to identify such a instance

// <smpl>
@@ expression E; @@
- if (E != NULL) { kfree(E); }
+ kfree(E);
@@ expression E; @@
- if (E != NULL) { kfree(E); E = NULL; }
+ kfree(E);
+ E = NULL;
// </smpl>

As rxb is always null at this point, so the code to kfree it and intializing
it to NULL is removed completely.

Suggested by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtllib_rx.c

@@ -1415,10 +1415,6 @@ static int rtllib_rx_InfraAdhoc(struct rtllib_device *ieee, struct sk_buff *skb,
 	return 1;
 
  rx_dropped:
-	if (rxb != NULL) {
-		kfree(rxb);
-		rxb = NULL;
-	}
 	ieee->stats.rx_dropped++;
 
 	/* Returning 0 indicates to caller that we have not handled the SKB--