ARM: constify machine_desc structure uses

struct machine_desc records are defined everywhere as a 'const'
structure, but unfortuantely it loses its const-ness through the use of
linker magic - the symbols which surround the section are not declared
const so it becomes possible not to use 'const' for pointers to these
const structures.

Let's fix this oversight - all pointers to these structures should be
marked const too.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4f56617..56054ac 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1151,7 +1151,7 @@
  * called function.  This means you can't use any function or debugging
  * method which may touch any device, otherwise the kernel _will_ crash.
  */
-static void __init devicemaps_init(struct machine_desc *mdesc)
+static void __init devicemaps_init(const struct machine_desc *mdesc)
 {
 	struct map_desc map;
 	unsigned long addr;
@@ -1272,7 +1272,7 @@
  * paging_init() sets up the page tables, initialises the zone memory
  * maps, and sets up the zero page, bad page and bad page tables.
  */
-void __init paging_init(struct machine_desc *mdesc)
+void __init paging_init(const struct machine_desc *mdesc)
 {
 	void *zero_page;