powerpc/mpic: Search for open-pic device-tree node if NULL

Almost all PowerPC platforms use a standard "open-pic" device node so
the mpic_alloc() function now accepts NULL for the device-node.  This
will cause it to perform a default search with of_find_matching_node().

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/85xx/mpc85xx_ds.c b/arch/powerpc/platforms/85xx/mpc85xx_ds.c
index 4fc6b80..104a09b 100644
--- a/arch/powerpc/platforms/85xx/mpc85xx_ds.c
+++ b/arch/powerpc/platforms/85xx/mpc85xx_ds.c
@@ -63,27 +63,21 @@
 void __init mpc85xx_ds_pic_init(void)
 {
 	struct mpic *mpic;
-	struct device_node *np;
 #ifdef CONFIG_PPC_I8259
+	struct device_node *np;
 	struct device_node *cascade_node = NULL;
 	int cascade_irq;
 #endif
 	unsigned long root = of_get_flat_dt_root();
 
-	np = of_find_node_by_type(NULL, "open-pic");
-	if (np == NULL) {
-		printk(KERN_ERR "Could not find open-pic node\n");
-		return;
-	}
-
 	if (of_flat_dt_is_compatible(root, "fsl,MPC8572DS-CAMP")) {
-		mpic = mpic_alloc(np, 0,
+		mpic = mpic_alloc(NULL, 0,
 			MPIC_PRIMARY |
 			MPIC_BIG_ENDIAN | MPIC_BROKEN_FRR_NIRQS |
 			MPIC_SINGLE_DEST_CPU,
 			0, 256, " OpenPIC  ");
 	} else {
-		mpic = mpic_alloc(np, 0,
+		mpic = mpic_alloc(NULL, 0,
 			  MPIC_PRIMARY | MPIC_WANTS_RESET |
 			  MPIC_BIG_ENDIAN | MPIC_BROKEN_FRR_NIRQS |
 			  MPIC_SINGLE_DEST_CPU,
@@ -91,8 +85,6 @@
 	}
 
 	BUG_ON(mpic == NULL);
-	of_node_put(np);
-
 	mpic_init(mpic);
 
 #ifdef CONFIG_PPC_I8259