of: base: make small of_parse_phandle() variants static inline

Make all the smaller variants of the of_parse_phandle() static inline.
This also let us remove the empty function stubs if CONFIG_OF is not
defined.

Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Walle <michael@walle.cc>
[robh: move index < 0 check into __of_parse_phandle_with_args]
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220118173504.2867523-2-michael@walle.cc