Various drivers' irq handlers: kill dead code, needless casts

- Eliminate casts to/from void*

- Eliminate checks for conditions that never occur.  These typically
  fall into two classes:

	1) Checking for 'dev_id == NULL', then it is never called with
	NULL as an argument.

	2) Checking for invalid irq number, when the only caller (the
	system) guarantees the irq handler is called with the proper
	'irq' number argument.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/serial/68360serial.c b/drivers/serial/68360serial.c
index 4e56ec8..634ecca 100644
--- a/drivers/serial/68360serial.c
+++ b/drivers/serial/68360serial.c
@@ -620,7 +620,7 @@
 	volatile struct smc_regs *smcp;
 	volatile struct scc_regs *sccp;
 	
-	info = (ser_info_t *)dev_id;
+	info = dev_id;
 
 	idx = PORT_NUM(info->state->smc_scc_num);
 	if (info->state->smc_scc_num & NUM_IS_SCC) {
diff --git a/drivers/serial/jsm/jsm_neo.c b/drivers/serial/jsm/jsm_neo.c
index 8fa31e6..8be8da3 100644
--- a/drivers/serial/jsm/jsm_neo.c
+++ b/drivers/serial/jsm/jsm_neo.c
@@ -1116,7 +1116,7 @@
  */
 static irqreturn_t neo_intr(int irq, void *voidbrd)
 {
-	struct jsm_board *brd = (struct jsm_board *) voidbrd;
+	struct jsm_board *brd = voidbrd;
 	struct jsm_channel *ch;
 	int port = 0;
 	int type = 0;
diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index 039c2fd..4f80c5b 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -512,19 +512,11 @@
 static irqreturn_t 
 mpc52xx_uart_int(int irq, void *dev_id)
 {
-	struct uart_port *port = (struct uart_port *) dev_id;
+	struct uart_port *port = dev_id;
 	unsigned long pass = ISR_PASS_LIMIT;
 	unsigned int keepgoing;
 	unsigned short status;
 	
-	if ( irq != port->irq ) {
-		printk( KERN_WARNING
-		        "mpc52xx_uart_int : " \
-		        "Received wrong int %d. Waiting for %d\n",
-		       irq, port->irq);
-		return IRQ_NONE;
-	}
-	
 	spin_lock(&port->lock);
 	
 	/* While we have stuff to do, we continue */
diff --git a/drivers/serial/netx-serial.c b/drivers/serial/netx-serial.c
index e92d7e1..062bad4 100644
--- a/drivers/serial/netx-serial.c
+++ b/drivers/serial/netx-serial.c
@@ -247,7 +247,7 @@
 
 static irqreturn_t netx_int(int irq, void *dev_id)
 {
-	struct uart_port *port = (struct uart_port *)dev_id;
+	struct uart_port *port = dev_id;
 	unsigned long flags;
 	unsigned char status;
 
diff --git a/drivers/serial/pxa.c b/drivers/serial/pxa.c
index 846089f..415fe96 100644
--- a/drivers/serial/pxa.c
+++ b/drivers/serial/pxa.c
@@ -232,7 +232,7 @@
  */
 static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id)
 {
-	struct uart_pxa_port *up = (struct uart_pxa_port *)dev_id;
+	struct uart_pxa_port *up = dev_id;
 	unsigned int iir, lsr;
 
 	iir = serial_in(up, UART_IIR);