scsi: mpt3sas: Add io_uring iopoll support

Enable the driver to work in non-IRQ mode, i.e. there will not be any MSI-X
vectors associated with queues dedicated to polling. The IOC hardware is
single submission queue and multiple reply queue. However, using the shared
host tagset support it is possible to simulate multiple hardware queues.

When poll_queues are enabled through the module parameter, the driver will
allocate extra reply queues without an MSI-X association. All I/O
completion on these queues will be done through the iopoll interface.

Link: https://lore.kernel.org/r/20210727081212.2742-1-sreekanth.reddy@broadcom.com


Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>