of: property: Fix the semantics of of_is_ancestor_of()

of: property: Fix the semantics of of_is_ancestor_of()

The of_is_ancestor_of() function was renamed from of_link_is_valid()
based on review feedback. The rename meant the semantics of the function
had to be inverted, but this was missed in the earlier patch.

So, fix the semantics of of_is_ancestor_of() and invert the conditional
expressions where it is used.

Fixes: 90329aa164c1 ("of: property: Add functional dependency link from DT bindings")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191120080230.16007-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>