[POWERPC] Use const qualifiers for prom parsing utilites

The of_bus callbacks map and get_flags can be constified, as they don't
alter the range or addr arguments. of_dump_addr and of_read_addr can
also be constified.

Built for 32- and 64-bit powerpc

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h
index b095a28..56f6ea0 100644
--- a/include/asm-powerpc/prom.h
+++ b/include/asm-powerpc/prom.h
@@ -198,7 +198,7 @@
 
 
 /* Helper to read a big number */
-static inline u64 of_read_number(u32 *cell, int size)
+static inline u64 of_read_number(const u32 *cell, int size)
 {
 	u64 r = 0;
 	while (size--)