MAINTAINERS: update entry for drivers/power/avs
MAINTAINERS: update entry for drivers/power/avs

Some more AVS-related drivers are arriving.  Update MAINTAINERS to
reflect that myself and Nishanth will keep an eye on the new ones as
well.

Signed-off-by: Kevin Hilman <f9849b02abe18c1ece6bd40346458ed53f49d31b@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs