[SPARC64]: constify of_get_property return: arch/sparc64

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/isa.c b/arch/sparc64/kernel/isa.c
index 98721a8..791eeb7 100644
--- a/arch/sparc64/kernel/isa.c
+++ b/arch/sparc64/kernel/isa.c
@@ -24,7 +24,7 @@
 
 static void __init isa_dev_get_resource(struct sparc_isa_device *isa_dev)
 {
-	struct linux_prom_registers *pregs;
+	const struct linux_prom_registers *pregs;
 	unsigned long base, len;
 	int prop_len;