Addition of support for if_type=6 missed several checks for interface type,
resulting in the failure of several key management features such as
firmware dump and loopback testing.

Correct the checks on the if_type so that both SLI4 IF_TYPE's 2 and 6 are
supported.
Signed-off-by: NDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: NJames Smart <jsmart2021@gmail.com>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>