i2c-omap: fix type of irq handler function

The probe function used a pointer to the interrupt
handler to register as a 'void *', change it to the
proper type of irq_handler_t.

Signed-off-by: Ben Dooks <[e-mail]>

drivers/i2c/busses/i2c-omap.c

···
 	struct omap_i2c_dev	*dev;
 	struct i2c_adapter	*adap;
 	struct resource		*mem, *irq, *ioarea;
-	void *isr;
+	irq_handler_t isr;
 	int r;
 	u32 speed = 0;