of: Support matching cpu nodes with no 'reg' property

For some single core ARM systems, the DTs can have a single cpu node
without a reg property and #address-cells == 0. This case is valid and
should match on cpu #0.

Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/base.c

@@ -327,6 +327,8 @@ static bool __of_find_n_match_cpu_property(struct device_node *cpun,
 
 	ac = of_n_addr_cells(cpun);
 	cell = of_get_property(cpun, prop_name, &prop_len);
+	if (!cell && !ac && arch_match_cpu_phys_id(cpu, 0))
+		return true;
 	if (!cell || !ac)
 		return false;
 	prop_len /= sizeof(*cell) * ac;