Define a new disk controller type in dkio.h
#define DKC_VBD 23
to be used by Solaris xVM disk drivers to indicate the disk is a virtual block device.
Solaris install makes decisions and takes actions based on the disk controller type being
installed onto. Integrating this change into Solaris prior to the xVM project allows the
install changes to be putback prior to the xVM integration and avoid cross-consolidation
sychronization issues.