[PATCH] powerpc: replace page_to_virt() with lowmem_page_address() for Book-E

page_to_virt and lowmem_page_address provided equiavlent functionality
so use the more standard lowmem_page_address

This also addresses build issue in ARCH=powerpc since page_to_virt()
has been removed from include/asm-powerpc/page.h
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/asm-ppc/pgalloc.h

@@ -28,7 +28,7 @@ extern void pgd_free(pgd_t *pgd);
 #define pmd_populate_kernel(mm, pmd, pte)	\
 		(pmd_val(*(pmd)) = (unsigned long)pte | _PMD_PRESENT)
 #define pmd_populate(mm, pmd, pte)	\
-		(pmd_val(*(pmd)) = (unsigned long)page_to_virt(pte) | _PMD_PRESENT)
+		(pmd_val(*(pmd)) = (unsigned long)lowmem_page_address(pte) | _PMD_PRESENT)
 #endif
 
 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);