scsi: mpt3sas: Rename mpi endpoint device ID macro.

MPI Endpoint is a PCIe switch based on MPI2.

Renaming device ID macro from MPI2_MFGPAGE_DEVID_SAS2308_MPI_EP to
MPI2_MFGPAGE_DEVID_SWITCH_MPI_EP.

Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>