sparc64: enhance VIO device probing

- Allocate IRQs for VIO devices during probing.
- Allow clients to specify if IRQs would be allocated for a given
  VIO device.
- Cache the device handle of the root node of channel-devices sub-tree in
  Machine Description (MDESC).

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/vio.h

@@ -336,6 +336,10 @@ struct vio_dev {
 	unsigned int		tx_irq;
 	unsigned int		rx_irq;
 	u64			rx_ino;
+	u64			tx_ino;
+
+	/* Handle to the root of "channel-devices" sub-tree in MDESC */
+	u64			cdev_handle;
 
 	struct device		dev;
 };
@@ -349,6 +353,7 @@ struct vio_driver {
 	void (*shutdown)(struct vio_dev *dev);
 	unsigned long			driver_data;
 	struct device_driver		driver;
+	bool				no_irq;
 };
 
 struct vio_version {