drivers/char: minor irq handler cleanups

- remove always-false tests

- don't overload 'irq' argument, pass data properly via dev_id

- remove pointless casts from void*

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 1f954ac..3c89266 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -491,7 +491,6 @@
 static void isr_rdma(struct slgt_info *info);
 static void isr_txeom(struct slgt_info *info, unsigned short status);
 static void isr_tdma(struct slgt_info *info);
-static irqreturn_t slgt_interrupt(int irq, void *dev_id);
 
 static int  alloc_dma_bufs(struct slgt_info *info);
 static void free_dma_bufs(struct slgt_info *info);
@@ -2326,17 +2325,13 @@
  * 	irq	interrupt number
  * 	dev_id	device ID supplied during interrupt registration
  */
-static irqreturn_t slgt_interrupt(int irq, void *dev_id)
+static irqreturn_t slgt_interrupt(int dummy, void *dev_id)
 {
-	struct slgt_info *info;
+	struct slgt_info *info = dev_id;
 	unsigned int gsr;
 	unsigned int i;
 
-	DBGISR(("slgt_interrupt irq=%d entry\n", irq));
-
-	info = dev_id;
-	if (!info)
-		return IRQ_NONE;
+	DBGISR(("slgt_interrupt irq=%d entry\n", info->irq_level));
 
 	spin_lock(&info->lock);
 
@@ -2385,7 +2380,7 @@
 
 	spin_unlock(&info->lock);
 
-	DBGISR(("slgt_interrupt irq=%d exit\n", irq));
+	DBGISR(("slgt_interrupt irq=%d exit\n", info->irq_level));
 	return IRQ_HANDLED;
 }