doc: release-notes: document DT_ENUM_IDX_OR

This is a new DT macro which was added in
c3eef7744aa9f43452ad2f88427406db9bf0fe70 ("include/devicetree.h: Add
DT_ENUM_IDX_OR macro")

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
1 file changed