The revision compat check for ZBX hardware is broken. It requires the
rev_compat register to read 1. However, that is the value for RevA,
which we are deliberately *not* supporting.
Supported revisions are B and C, which have a rev_compat value of 2. We
therefore change the check to support revision 2, but not 1. In the
future, we would support revisions 2 and up if there are more revs to
ZBX. Valid rev_compat values are tracked in a whitelist (which we need
to update as we produce more revisions).
This patch fixes an issue where MPM wouldn't start when ZBX revisions
B or C are plugged in.
99bb7b2127