scsi: cxlflash: Separate RRQ processing from the RRQ interrupt handler

scsi: cxlflash: Separate RRQ processing from the RRQ interrupt handler

BugLink: http://bugs.launchpad.net/bugs/1702521
In order to support processing the HRRQ by other means (e.g. polling), the
processing portion of the current RRQ interrupt handler needs to be broken out
into a separate routine. This will allow RRQ processing from places other than
the RRQ hardware interrupt handler.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit 76a6ebbeef26b004c36a0c8ee0496bae5428fc31)
Signed-off-by: Victor Aoqui <victora@linux.vnet.ibm.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>