powerpc/boot: Define typedef ihandle as u32

This makes ihandle 64bit friendly.

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/boot/of.h b/arch/powerpc/boot/of.h
index 504a0a3..e1ef620 100644
--- a/arch/powerpc/boot/of.h
+++ b/arch/powerpc/boot/of.h
@@ -2,7 +2,7 @@
 #define _PPC_BOOT_OF_H_
 
 typedef void *phandle;
-typedef void *ihandle;
+typedef u32 ihandle;
 
 void of_init(void *promptr);
 int of_call_prom(const char *service, int nargs, int nret, ...);