Merge with latest version of the Mylex 6+ driver.

Merge with latest version of the Mylex 6+ driver.

 - All sources are built in a single object, reducing namespace pollution.
 - Kill the ready queue, and handle a busy response to mly_start in callers
   rather than deferring the command.
 - Improve our interaction with CAM:
   - Don't advertise physical channels as SCSI busses by default.
   - use the SIM queue freeze capability rather than queueing CDBs internally.
   - force bus reprobe at module load time.
 - Clean up more resources in mly_free.
 - Tidy up debugging levels.
 - Tidy up handling of events (mostly just code cleanliness).
 - Use explanatory macros for operations on bus/target/channel numbers.