scsi: mpt3sas: Fix NULL pointer access in mpt3sas_transport_port_add()

In the Linux kernel, the following vulnerability has been resolved: scsi: mpt3sas: Fix NULL pointer access in mpt3sas_transport_port_add() Port is allocated by sas_port_alloc_num() and rphy is allocated by either sas_end_device_alloc() or sas_expander_alloc(), all of which may return NULL. So we need to check the rphy to avoid possible NULL pointer access. If sas_rphy_add() returned with failure, rphy is set to NULL. We would access the rphy in the following lines which would also result NULL pointer access.