of/fdt: fix error checking for earlycon address

commit 3f5ceec9 upstream.

fdt_translate_address() returns OF_BAD_ADDR on error.  It is defined as
a u64 value, so the variable "addr" should be defined as u64 as well.

Fixes: fb11ffe7 ("of/fdt: add FDT serial scanning for earlycon")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/of/fdt.c

@@ -774,14 +774,15 @@ int __init early_init_dt_scan_chosen_serial(void)
 		return -ENODEV;
 
 	while (match->compatible[0]) {
-		unsigned long addr;
+		u64 addr;
+
 		if (fdt_node_check_compatible(fdt, offset, match->compatible)) {
 			match++;
 			continue;
 		}
 
 		addr = fdt_translate_address(fdt, offset);
-		if (!addr)
+		if (addr == OF_BAD_ADDR)
 			return -ENXIO;
 
 		of_setup_earlycon(addr, match->data);