[viostor] Programmatically determine max_segments

Refactors VirtIoFindAdapter() to:

1. Enable Registry lookup for max_segments in value "MaxPhysicalSegments"
2. Refactor existing options into proposed vioscsi scaffold
3. Calc sectors from geometry and segments from sectors
4. Choose from among best candidates and check within limits
5. Enforce legacy StorPort NOPB off-by-one behaviour and provide explanation
6. Improves relevant instrumentation

Note: This commit enables the use of max_segments greater than
      info.seg_max (max = 254) up to MAX_PHYS_SEGMENTS (presently 512).
      This commit also fixes a NOPB off-by-one regression.

Signed-off-by: benyamin-codez <[email protected]>

Author: benyamin-codez