powerpc: Fix problems with 32bit PPC's running with >= 4GB of RAM

This patch enables 32bit PPC's (with 36bit physical address space, e.g.
IBM/AMCC PPC44x) to run with >= 4GB of RAM. Mostly its just replacing types
(unsigned long -> phys_addr_t).

Tested on an AMCC Katmai with 4GB of DDR2.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 4541859..388ceda 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -57,8 +57,8 @@
 
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 
-unsigned long total_memory;
-unsigned long total_lowmem;
+phys_addr_t total_memory;
+phys_addr_t total_lowmem;
 
 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
 EXPORT_SYMBOL(memstart_addr);