MAINTAINERS: Move nvdimm mailing list

After seeing some users have subscription management trouble, more spam
than other Linux development lists, and considering some of the benefits
of kernel.org hosted lists, nvdimm and persistent memory development is
moving to nvdimm@lists.linux.dev.

The old list will remain up until v5.14-rc1 and shutdown thereafter.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Link: https://lore.kernel.org/r/161898872871.3406469.4054282559340528393.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: Dan Williams <dan.j.williams@intel.com>