ptp: ocp: correct label for error path

When devlink_register() was removed from the error path, the
corresponding label was not updated.   Rename the label for
readability puposes, no functional change.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/r/20220308000458.2166-1-jonathan.lemon@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>