mailmap: Update philmd email address

Use the email address where I spend most of my time.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Message-Id: <20190822230916.576-3-philmd@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>