dm: core: fix member name in ofnode_union documentation

Fixes: 4984de2baaa ("dm: core: Add ofnode to represent device tree nodes")
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed