docs/MAINTAINERS: Update my email address

In the near future, I will not have access to the email address I used as
maintainer of a number of things, mostly in the documentation. Update that
address to my personal email address (see Link) so I can continue
contributing and update .mailmap.

Link: https://lore.kernel.org/all/BL1PR12MB58749FF2BFEDB817DE1FE6CBF82A2@BL1PR12MB5874.namprd12.prod.outlook.com/


Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/139b8cab-009c-4688-be41-c4c526532ea1@amd.com