staging: vt6655: Remove vif check from vnt_interrupt

BugLink: https://bugs.launchpad.net/bugs/1826212

commit cc26358f upstream.

A check for vif is made in vnt_interrupt_work.

There is a small chance of leaving interrupt disabled while vif
is NULL and the work hasn't been scheduled.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
CC: stable@vger.kernel.org # v4.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/staging/vt6655/device_main.c

@@ -1079,7 +1079,6 @@ static irqreturn_t vnt_interrupt(int irq,  void *arg)
 {
 	struct vnt_private *priv = arg;
 
-	if (priv->vif)
 	schedule_work(&priv->interrupt_work);
 
 	return IRQ_HANDLED;