nvme: update MAINTAINERS email address

Update the MAINTAINERS file email address.
Signed-off-by: NChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

MAINTAINERS

@@ -13367,7 +13367,7 @@ F:	include/linux/nvme-fc.h
 NVM EXPRESS TARGET DRIVER
 M:	Christoph Hellwig <hch@lst.de>
 M:	Sagi Grimberg <sagi@grimberg.me>
-M:	Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
+M:	Chaitanya Kulkarni <kch@nvidia.com>
 L:	linux-nvme@lists.infradead.org
 S:	Supported
 W:	http://git.infradead.org/nvme.git