MAINTAINERS: change maintainer for FSI

MAINTAINERS: change maintainer for FSI

Due to job transitions, both Joel and Jeremy can no longer maintain
the FSI subsystem. I will take over.
I also replaced Alistair with Ninad as a reviewer, as Alistair doesn't
have access to hardware and hasn't been active.
I also removed the link to Joel's FSI tree as he won't be maintaining
it.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Link: https://lore.kernel.org/r/20250213225746.2159118-1-eajames@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>