Update target repo for nvme patch contributions

Update target repo for nvme patch contributions

Per http://www.nvmexpress.org/resources/linux-driver-information/, the
old nvme git repo is stale.  Updating MAINTAINERS to the Supported
target currently used by the community.

Signed-off-by: Jay Freyensee <james_p_freyensee@linux.intel.com>
Updated by me to add Keith as the maintainer, me as the co-maintainer.

Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit b3975e94f5688691f487ea00126dabe8f5bee3af)

Orabug: 25130845
Signed-off-by: Ashok Vairavan <ashok.vairavan@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>