In some rare cases, the driver can halt the controller. Add a reason code
describing why the controller was halted.  Store this reason code in a
controller register to aid in debugging the issue.

Link: https://lore.kernel.org/r/20210928235442.201875-4-don.brace@microchip.comReviewed-by: Scott Benesh <scott.benesh@microchip.com>
Reviewed-by: Scott Teel <scott.teel@microchip.com>
Reviewed-by: Mike McGowen <mike.mcgowen@microchip.com>
Acked-by: John Donnelly <john.p.donnelly@oracle.com>
Signed-off-by: Murthy Bhat <Murthy.Bhat@microchip.com>
Signed-off-by: Don Brace <don.brace@microchip.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>