Add myself as the maintainer for the Xtensa architecture.
Add myself as the maintainer for the Xtensa architecture.

Signed-off-by: Chris Zankel <711c73f64afdce07b7e38039a96d2224209e9a6c@zankel.net>

joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc