staging: rtl8712: usb_ops_linux: Clean up tests if NULL returned on failure

Some functions like kmalloc/kzalloc return NULL on failure.
When NULL represents failure, !x is commonly used.

This was done using Coccinelle:

@@
expression *e;
identifier l1;
@@

e = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\)(...);
...
- e == NULL
+ !e
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/usb_ops_linux.c

@@ -504,7 +504,7 @@ int r8712_usbctrl_vendorreq(struct intf_priv *pintfpriv, u8 request, u16 value,
 	u8 *palloc_buf, *pIo_buf;
 
 	palloc_buf = kmalloc((u32)len + 16, GFP_ATOMIC);
-	if (palloc_buf == NULL)
+	if (!palloc_buf)
 		return -ENOMEM;
 	pIo_buf = palloc_buf + 16 - ((addr_t)(palloc_buf) & 0x0f);
 	if (requesttype == 0x01) {