[IA64] Rationalise Region Definitions

Currently, region numbers are defined in several files, with several 
names.  For example, we have REGION_KERNEL in asm/page.h and 
RGN_KERNEL in pgtable.h 
 
We also have address definitions that should depend on the 
RGN_XXX macros, but are currently just long constants. 
 
The following patch reorganises all the definitions so that they have 
the same form (RGN_XXX), are in one place, and that addresses that 
depend on RGN_XXX are derived from them. 

(This is a necessary but not sufficient patch to allow UML-like 
operation on IA64). 

Thanks to David Mosberger for catching the change I missed in mmu_context.h.
 
Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au> 
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index e0a776a..2d13889 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c
@@ -76,7 +76,7 @@
 		return -EINVAL;
 	if (addr & ~HPAGE_MASK)
 		return -EINVAL;
-	if (REGION_NUMBER(addr) != REGION_HPAGE)
+	if (REGION_NUMBER(addr) != RGN_HPAGE)
 		return -EINVAL;
 
 	return 0;
@@ -87,7 +87,7 @@
 	struct page *page;
 	pte_t *ptep;
 
-	if (REGION_NUMBER(addr) != REGION_HPAGE)
+	if (REGION_NUMBER(addr) != RGN_HPAGE)
 		return ERR_PTR(-EINVAL);
 
 	ptep = huge_pte_offset(mm, addr);
@@ -142,8 +142,8 @@
 		return -ENOMEM;
 	if (len & ~HPAGE_MASK)
 		return -EINVAL;
-	/* This code assumes that REGION_HPAGE != 0. */
-	if ((REGION_NUMBER(addr) != REGION_HPAGE) || (addr & (HPAGE_SIZE - 1)))
+	/* This code assumes that RGN_HPAGE != 0. */
+	if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 		addr = HPAGE_REGION_BASE;
 	else
 		addr = ALIGN(addr, HPAGE_SIZE);