MAINTAINERS: Update Srivatsa S. Bhat's maintained areas

I have decided to change employers and I'm not sure if I'll be able to
spend as much time on the subsystems/drivers I maintain. So, I would
like to remove myself from the maintainer role.

Remove Srivatsa from the maintainers entry and add Ajay Kaher as an
additional reviewer/maintainer for the respective areas. Also, add an
entry to CREDITS for Srivatsa.

  [ bp: Merge all three into one patch, adjust commit message. ]

Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Alexey Makhalov <amakhalov@vmware.com>
Acked-by: Ajay Kaher <akaher@vmware.com>
Acked-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230512164958.575174-1-srivatsa@csail.mit.edu