MAINTAINERS: add myself as maintainer for the fsl-mc bus

Both Laurentiu and Stuart left the company and are no longer involved
with the fsl-mc bus. Remove them and add myself as maintainer.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20250320120319.3520315-2-ioana.ciornei@nxp.com


Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>