[PATCH] powerpc: Replace VMALLOCBASE with VMALLOC_START

On ppc64, we independently define VMALLOCBASE and VMALLOC_START to be
the same thing: the start of the vmalloc() area at 0xd000000000000000.
VMALLOC_START is used much more widely, including in generic code, so
this patch gets rid of the extraneous VMALLOCBASE.

This does require moving the definitions of region IDs from page_64.h
to pgtable.h, but they don't clearly belong in the former rather than
the latter, anyway.  While we're moving them, clean up the definitions
of the REGION_IDs:
	- Abolish REGION_SIZE, it was only used once, to define
REGION_MASK anyway
	- Define the specific region ids in terms of the REGION_ID()
macro.
	- Define KERNEL_REGION_ID in terms of PAGE_OFFSET rather than
KERNELBASE.  It amounts to the same thing, but conceptually this is
about the region of the linear mapping (which starts at PAGE_OFFSET)
rather than of the kernel text itself (which is at KERNELBASE).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/lparmap.c b/arch/powerpc/kernel/lparmap.c
index 8a53d43..92d9474 100644
--- a/arch/powerpc/kernel/lparmap.c
+++ b/arch/powerpc/kernel/lparmap.c
@@ -18,8 +18,8 @@
 	.xEsids = {
 		{ .xKernelEsid = GET_ESID(PAGE_OFFSET),
 		  .xKernelVsid = KERNEL_VSID(PAGE_OFFSET), },
-		{ .xKernelEsid = GET_ESID(VMALLOCBASE),
-		  .xKernelVsid = KERNEL_VSID(VMALLOCBASE), },
+		{ .xKernelEsid = GET_ESID(VMALLOC_START),
+		  .xKernelVsid = KERNEL_VSID(VMALLOC_START), },
 	},
 
 	.xRanges = {