MAINTAINERS: TPM maintainers' contacts update

Usual contact update, Debora Velarde role resign, and the new
co-maintainer inclusion, Kent Yoder. He's accepted to contribute
more actively to this driver's maintainership given the current
maintainer's slight career change that will affect his contribution
time.

[Replacing Debora Velarde by Kent Yoder]
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>