MFC 271881: Fix partition alignment and image rounding when any of
-P (block size),  -T (track size) or -H (number of heads) is given.

Approved by:	re@ (gjb)
MFC r271429, r271882:
Add support for controlling mfi(4) controller properties

Approved by:	re (glebius)
Sponsored by:	Multiplay
Merge remote-tracking branch 'freebsd/stable/10' into hardened/10/aslr