arm64: mm: simplify the page end calculation in __create_pgd_mapping()

Calculate the page-aligned end address more simply.

The local variable, "length" is unneeded.
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/mmu.c

@@ -338,7 +338,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 				 phys_addr_t (*pgtable_alloc)(int),
 				 int flags)
 {
-	unsigned long addr, length, end, next;
+	unsigned long addr, end, next;
 	pgd_t *pgdp = pgd_offset_raw(pgdir, virt);
 
 	/*
@@ -350,9 +350,8 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 
 	phys &= PAGE_MASK;
 	addr = virt & PAGE_MASK;
-	length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
+	end = PAGE_ALIGN(virt + size);
 
-	end = addr + length;
 	do {
 		next = pgd_addr_end(addr, end);
 		alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,