MAINTAINERS / cpufreq: update Sudeep's email address

Though my old email address continues to work as alias, updating
to the new address as it's shorter, easier and more appropriate.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>