[POWERPC] Remove and replace uses of PPC_MEMSTART with memstart_addr

A number of users of PPC_MEMSTART (40x, ppc_mmu_32) can just always
use 0 as we don't support booting these kernels at non-zero physical
addresses since their exception vectors must be at 0 (or 0xfffx_xxxx).

For the sub-arches that support relocatable interrupt vectors
(book-e), it's reasonable to have memory start at a non-zero physical
address.  For those cases use the variable memstart_addr instead of
the #define PPC_MEMSTART since the only uses of PPC_MEMSTART are for
initialization and in the future we can set memstart_addr at runtime
to have a relocatable kernel.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c
index c93a966..3dd0c81 100644
--- a/arch/powerpc/mm/fsl_booke_mmu.c
+++ b/arch/powerpc/mm/fsl_booke_mmu.c
@@ -53,13 +53,12 @@
 #include <asm/machdep.h>
 #include <asm/setup.h>
 
+#include "mmu_decl.h"
+
 extern void loadcam_entry(unsigned int index);
 unsigned int tlbcam_index;
 unsigned int num_tlbcam_entries;
 static unsigned long __cam0, __cam1, __cam2;
-extern unsigned long total_lowmem;
-extern unsigned long __max_low_memory;
-extern unsigned long __initial_memory_limit;
 #define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE
 
 #define NUM_TLBCAMS	(16)
@@ -165,15 +164,15 @@
 void __init cam_mapin_ram(unsigned long cam0, unsigned long cam1,
 		unsigned long cam2)
 {
-	settlbcam(0, PAGE_OFFSET, PPC_MEMSTART, cam0, _PAGE_KERNEL, 0);
+	settlbcam(0, PAGE_OFFSET, memstart_addr, cam0, _PAGE_KERNEL, 0);
 	tlbcam_index++;
 	if (cam1) {
 		tlbcam_index++;
-		settlbcam(1, PAGE_OFFSET+cam0, PPC_MEMSTART+cam0, cam1, _PAGE_KERNEL, 0);
+		settlbcam(1, PAGE_OFFSET+cam0, memstart_addr+cam0, cam1, _PAGE_KERNEL, 0);
 	}
 	if (cam2) {
 		tlbcam_index++;
-		settlbcam(2, PAGE_OFFSET+cam0+cam1, PPC_MEMSTART+cam0+cam1, cam2, _PAGE_KERNEL, 0);
+		settlbcam(2, PAGE_OFFSET+cam0+cam1, memstart_addr+cam0+cam1, cam2, _PAGE_KERNEL, 0);
 	}
 }