block/nvme: Use generic NvmeBar structure

block/nvme: Use generic NvmeBar structure

Commit f3c507adcd7 ("NVMe: Initial commit for new storage interface")
introduced the NvmeBar structure. Unfortunately in commit bdd6a90a9e5
("block: Add VFIO based NVMe driver") we duplicated it.

Apparently in commit a3d9a352d48 ("block: Move NVMe constants to
a separate header") we tried to unify headers but forgot to remove
the structure declared in the block/nvme.c source file.

Do it now, and remove the structure size check which is redundant
with the header check added in commit 74e18435c0e ("hw/block/nvme:
Align I/O BAR to 4 KiB").

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200904124130.583838-3-philmd@redhat.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Fam Zheng <fam@euphon.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>