nvme: replace the "bool vec" arguments with flags in the ioctl path

To prepare for passing down more information, replace the boolean
vec argument with a more extensible flags one.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>