i2c: fix leaked device refcount on of_find_i2c_* error path

If of_find_i2c_device_by_node() or of_find_i2c_adapter_by_node() find
a device by node, but its type does not match, a reference to that
device is still held. This change fixes the problem.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>