of/fdt: fix memory range check

In cases where board has below memory DT node

memory{
	device_type = "memory";
	reg = <0x80000000 0x80000000>;
};

Check on the memory range in fdt.c will always fail because it is
comparing MAX_PHYS_ADDR with base + size, in fact it should compare
it with base + size - 1.

This issue was originally noticed on Qualcomm IFC6410 board.
Without this patch kernel shows up noticed unnecessary warnings

[    0.000000] Machine model: Qualcomm APQ8064/IFC6410
[    0.000000] Ignoring memory range 0xffffffff - 0x100000000
[    0.000000] cma: Reserved 64 MiB at ab800000

as a result the size get reduced to 0x7fffffff which looks wrong.

This patch fixes the check involved in generating this warning and
as a result it also fixes the wrong size calculation.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
[grant.likely: adjust new size calculation also]
Signed-off-by: Grant Likely <grant.likely@linaro.org>

drivers/of/fdt.c

@@ -941,10 +941,10 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 		return;
 	}
 
-	if (base + size > MAX_PHYS_ADDR) {
-		pr_warning("Ignoring memory range 0x%lx - 0x%llx\n",
-				ULONG_MAX, base + size);
-		size = MAX_PHYS_ADDR - base;
+	if (base + size - 1 > MAX_PHYS_ADDR) {
+		pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
+				((u64)MAX_PHYS_ADDR) + 1, base + size);
+		size = MAX_PHYS_ADDR - base + 1;
 	}
 
 	if (base + size < phys_offset) {