ptp_ocp: adjust MAINTAINERS and mailmap

The fb.com domain is going to be deprecated.
Use personal one for kernel contributions.

Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240104172540.2379128-1-vadfed@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>