arm64: ptdump: Indicate whether memory should be faulting

With CONFIG_DEBUG_PAGEALLOC, pages do not have the valid bit
set when free in the buddy allocator. Add an indiciation to
the page table dumping code that the valid bit is not set,
'F' for fault, to make this easier to understand.
Reviewed-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Tested-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NLaura Abbott <labbott@fedoraproject.org>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/dump.c

@@ -90,6 +90,11 @@ struct prot_bits {
 
 static const struct prot_bits pte_bits[] = {
 	{
+		.mask	= PTE_VALID,
+		.val	= PTE_VALID,
+		.set	= " ",
+		.clear	= "F",
+	}, {
 		.mask	= PTE_USER,
 		.val	= PTE_USER,
 		.set	= "USR",