MAINTAINERS: Add a maintainer for OCP Time Card

I've been contributing and reviewing patches for ptp_ocp driver for
some time and I'm taking care of it's github mirror. On Jakub's
suggestion, I would like to step forward and become a maintainer for
this driver. This patch adds a dedicated entry to MAINTAINERS.

Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/r/20220621233131.21240-1-vfedorenko@novek.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>