nvme: fix LBA format data structure

The LBA Format Data structure is dword-sized, but struct nvme_lba_format
erroneously contains an additional member, misaligning all LBAF
descriptors after the first and causing them to be misinterpreted.
Remove it.

Signed-off-by: Florian Larysch <fl@n621.de>
Reviewed-by: Alexander Graf <graf@amazon.com>