MAINTAINERS: Adjust maintainer's email

MAINTAINERS: Adjust maintainer's email

For some longish time I've been using multiple email addresses
for mailing list communication, and would like to consolidate it
into a single email address that is the most convenient to me.
My other emails, from rt-rk.com and wavecomp.com domains remain
active and I will respond from them too, if needed, but I would
like to manage almost all communication using gmail.com account.

Signed-off-by: Aleksandar Markovic <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <1584061252[email protected]>