i2c-mv64xxx: correct mv64xxx_i2c_intr() return type

The mv64xxx_i2c_intr() irq handler in drivers/i2c/busses/i2c-mv64xxx.c
is declared as returning 'int', resulting in this compile-time warning:

drivers/i2c/busses/i2c-mv64xxx.c: In function 'mv64xxx_i2c_probe':
drivers/i2c/busses/i2c-mv64xxx.c:540: warning: passing argument 2 of 'request_irq' from incompatible pointer type

Fix: correct the return type to 'irqreturn_t'.
Signed-off-by: NMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

drivers/i2c/busses/i2c-mv64xxx.c

@@ -293,13 +293,13 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
 	}
 }
 
-static int
+static irqreturn_t
 mv64xxx_i2c_intr(int irq, void *dev_id)
 {
 	struct mv64xxx_i2c_data	*drv_data = dev_id;
 	unsigned long	flags;
 	u32		status;
-	int		rc = IRQ_NONE;
+	irqreturn_t	rc = IRQ_NONE;
 
 	spin_lock_irqsave(&drv_data->lock, flags);
 	while (readl(drv_data->reg_base + MV64XXX_I2C_REG_CONTROL) &