[PATCH 1/3] nvme: Add Arbitration Burst support

[Sagi Grimberg]

>>  From the NVMe spec, "In order to make efficient use of the non-volatile
>> memory, it is often advantageous to execute multiple commands from a
>> Submission Queue in parallel. For Submission Queues that are using
>> weighted round robin with urgent priority class or round robin
>> arbitration, host software may configure an Arbitration Burst setting".
>> Thus add Arbitration Burst setting support.
> 
> But if the user changed it to something else that better matches how
> they want to use queues, the driver is just going to undo that setting
> on the next reset.

Where do we do priority class arbitration? no one sets it