gpio: Disable functions not used with of-platdata

These functions use devicetree and cannot work with of-platdata, which has
no runtime devicetree.

If they are used, the current linker error is confusing, since it talks
about missing functions in the bowels of driver model.

Avoid compiling these functions at all with of-platdata, so that a
straightforward link error points to the problem.

Series-changes; 3
- Fix 'wprl' typo

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>