Staging: rtl8712: Clean up tests if NULL returned on failure

Some functions like kmalloc/usb_alloc_urb/kmalloc_array returns NULL as
their return value on failure. !x is generally preferred over x==NULL
or NULL==x so make use of !x if the value returned on failure
by these functions is NULL.
Done using coccinelle:

@@
expression e;
statement S;
@@
e = \(kmalloc\|devm_kzalloc\|kmalloc_array
     \|devm_ioremap\|usb_alloc_urb\|alloc_netdev\)(...);
- if(e==NULL)
+ if(!e)
  S

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/rtl8712/rtl871x_io.c b/drivers/staging/rtl8712/rtl871x_io.c
index fbbc635..3a10940 100644
--- a/drivers/staging/rtl8712/rtl871x_io.c
+++ b/drivers/staging/rtl8712/rtl871x_io.c
@@ -113,7 +113,7 @@
 	struct io_req *pio_req;
 
 	pio_queue = kmalloc(sizeof(*pio_queue), GFP_ATOMIC);
-	if (pio_queue == NULL)
+	if (!pio_queue)
 		goto alloc_io_queue_fail;
 	INIT_LIST_HEAD(&pio_queue->free_ioreqs);
 	INIT_LIST_HEAD(&pio_queue->processing);