iichid(4): Perform bus_teardown_intr/bus_setup_intr to disable interrupts

during suspend/resume cycle. Previously used bus_generic_suspend_intr and
bus_generic_resume_intr may cause interrupt storm because of missed
interrupt acknowledges caused by blocking of intr handler.

Reported by: J.R. Oldroyd <jr_AT_opal_DOT_com>
MFC after: 1 week