Add fwnode_is_ancestor_of() helper function to check if a fwnode is an
ancestor of another fwnode.

Add fwnode_get_next_parent_dev() helper function that take as input a
fwnode and finds the closest ancestor fwnode that has a corresponding
struct device and returns that struct device.
Signed-off-by: NSaravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-11-saravanak@google.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>