ARM: pgtable: provide get_top_pte() to complement set_top_pte()

Provide get_top_pte() to complement set_top_pte(), moving the only
users of TOP_PTE to arch/arm/mm/mm.h.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index a4e7feb..1651d5a 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -24,6 +24,11 @@
 	local_flush_tlb_kernel_page(va);
 }
 
+static inline pte_t get_top_pte(unsigned long va)
+{
+	return *TOP_PTE(va);
+}
+
 static inline pmd_t *pmd_off_k(unsigned long virt)
 {
 	return pmd_offset(pud_offset(pgd_offset_k(virt), virt), virt);