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 <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/rtl8192e/rtl819x_BAProc.c

···
 		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));
···
 	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);