bhyve: Fix Number of Power States Supported value
Summary:
Set Number of Power States Supported to indicate 1 power state. Keep the
Power State Descriptor data structures as zero to indicate "Not
reported".
Test Plan:
Within FreeBSD/Linux guests, list the number of power states and check
the Max Power value.
Reviewed By: markj, chuck
MFC after: 2 weeks
Signed-off-by: Wanpeng Qian <wanpengqian@gmail.com>
Differential Revision: https://reviews.freebsd.org/D32657