scsi: cxlflash: Explicitly cache number of interrupts per context

The number of interrupts a user requests during a context attach is
presently stored within the CXL work ioctl structure that is nested
alongside the per context metadata. Keeping this data in a structure
that is tied to a particular hardware implementation (CXL) will only
complicate matters when supporting newer accelerator transports.

Instead of relying upon the number of interrupts being cached within
a CXL-specific structure, explicitly cache the value within the context
information structure.

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>