powerpc: fsl_msi doesn't need it's own of_node

The FSL MSI code keeps a pointer to the of_node from the device
it represents.  However it also has an irq_host, which contains
a pointer to the of_node, so use that one instead.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/sysdev/fsl_msi.h

@@ -22,9 +22,6 @@
 #define FSL_PIC_IP_IPIC	0x00000002
 
 struct fsl_msi {
-	/* Device node of the MSI interrupt*/
-	struct device_node *of_node;
-
 	struct irq_host *irqhost;
 
 	unsigned long cascade_irq;