staging: rtl8192e: replace explicit NULL comparison

Replace explicit NULL comparison with ! operator to
simplify code.

Found with Coccinelle script:
@@
expression ptr;
position p;
statement s0, s1;
@@

ptr@p =
\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|usb_alloc_urb\|
alloc_netdev\|dev_alloc_skb\)(...)
... when != ptr

if (
(
+ !
ptr
- == NULL
)
) s0 else s1

Signed-off-by: Gargi Sharma <gs051095@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtl819x_BAProc.c

@@ -88,7 +88,7 @@ static struct sk_buff *rtllib_ADDBA(struct rtllib_device *ieee, u8 *Dst,
 		return NULL;
 	}
 	skb = dev_alloc_skb(len + sizeof(struct rtllib_hdr_3addr));
-	if (skb == NULL)
+	if (!skb)
 		return NULL;
 
 	memset(skb->data, 0, sizeof(struct rtllib_hdr_3addr));
@@ -154,7 +154,7 @@ static struct sk_buff *rtllib_DELBA(struct rtllib_device *ieee, u8 *dst,
 	DelbaParamSet.field.TID	= pBA->BaParamSet.field.TID;
 
 	skb = dev_alloc_skb(len + sizeof(struct rtllib_hdr_3addr));
-	if (skb == NULL)
+	if (!skb)
 		return NULL;
 
 	skb_reserve(skb, ieee->tx_headroom);