[Bluetooth] Eliminate checks for impossible conditions in IRQ handler

Our info structure and info->hdev is always passed to the IRQ handler,
so we don't have to worry about these checks in every interrupt.

Leave a BUG_ON() just to help unwary programmers, but these could
probably be removed as well.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/dtl1_cs.c

@@ -298,10 +298,7 @@ static irqreturn_t dtl1_interrupt(int irq, void *dev_inst)
 	int boguscount = 0;
 	int iir, lsr;
 
-	if (!info || !info->hdev) {
-		BT_ERR("Call of irq %d for unknown device", irq);
-		return IRQ_NONE;
-	}
+	BUG_ON(!info->hdev);
 
 	iobase = info->p_dev->io.BasePort1;