powerpc: Change memory_limit from phys_addr_t to unsigned long long

There are some device-tree nodes, whose values are of type phys_addr_t.
The phys_addr_t is variable sized based on the CONFIG_PHSY_T_64BIT.

Change these to a fixed unsigned long long for consistency.

This patch does the change only for memory_limit.

The following is a list of such variables which need the change:

 1) kernel_end, crashk_size - in arch/powerpc/kernel/machine_kexec.c

 2) (struct resource *)crashk_res.start - We could export a local static
    variable from machine_kexec.c.

Changing the above values might break the kexec-tools. So, I will
fix kexec-tools first to handle the different sized values and then change
 the above.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index f191bf0..37725e8 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -78,7 +78,7 @@
 		return 1;
 
 	memory_limit = PAGE_ALIGN(memparse(p, &p));
-	DBG("memory limit = 0x%llx\n", (unsigned long long)memory_limit);
+	DBG("memory limit = 0x%llx\n", memory_limit);
 
 	return 0;
 }
@@ -661,7 +661,7 @@
 
 	/* make sure we've parsed cmdline for mem= before this */
 	if (memory_limit)
-		first_memblock_size = min(first_memblock_size, memory_limit);
+		first_memblock_size = min_t(u64, first_memblock_size, memory_limit);
 	setup_initial_memory_limit(memstart_addr, first_memblock_size);
 	/* Reserve MEMBLOCK regions used by kernel, initrd, dt, etc... */
 	memblock_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);