scsi: cxlflash: Adapter context init can return error

scsi: cxlflash: Adapter context init can return error

BugLink: http://bugs.launchpad.net/bugs/1752672
Adapter context creation can return either NULL or an error pointer.
Updating the check condition to reflect this.

Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit 0df69c6024cd089144d3b38f12352899dd4e40b1)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>