Extend EM support in ahci driver to support SGPIO messages
The enclosure management (EM) support in the ahci driver currently only supports the LED message type for controlling drive bay LEDs.
We recently encountered a Supermicro platform where the onboard SATA HBA (which drives a pair of rear drive bays) reports only supporting the LED message type. However. testing under both SmartOS and Linux showed that in reality, the HBA only supported the SGPIO message type.
This ticket is to extend the current EM LED support in the ahci driver to support SGPIO messages.