powerpc: Move free_initmem to common code

The free_initmem function is basically duplicated in mm/init_32,
and init_64, and is moved to the common 32/64-bit mm/mem.c.

All other sections except init were removed in v2.6.15 by
6c45ab992e (powerpc: Remove section
free() and linker script bits), and therefore the bulk of the executed
code is identical.

This patch also removes updating ppc_md.progress to NULL in the powermac
late_initcall.

Suggested-by: Milton Miller <miltonm@bga.com>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powermac/setup.c

@@ -355,9 +355,6 @@ static int initializing = 1;
 static int pmac_late_init(void)
 {
 	initializing = 0;
-	/* this is udbg (which is __init) and we can later use it during
-	 * cpu hotplug (in smp_core99_kick_cpu) */
-	ppc_md.progress = NULL;
 	return 0;
 }
 machine_late_initcall(powermac, pmac_late_init);