The port mask used for per-port sensors in mcdi_sensor_map
assumes zero-based port numbering. The port mask used in
the code is based on the one-based MCDI port number.
Fix this to lookup the correct per-port sensors, and to
allow reporting of sensor events from higher port numbers.
Submitted by: Andy Moreton <amoreton at solarflare.com>
Sponsored by: Solarflare Communications, Inc.
MFC after: 2 days