Fix hang on soft reboot after:

PCI Express-device: pci8086,e08@3, pcieb3
pcieb3 is /pci@0,0/pci8086,e08@3
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^hangs
# but should continue with:

PCIE-device: pci1000,3020@0, mpt_sas0
PCI Express-device: pci1000,3020@0, mpt_sas0
mpt_sas0 is /pci@0,0/pci8086,e08@3/pci1000,3020@0
mpt_sas6 at mpt_sas0: scsi-iport 8
mpt_sas6 is /pci@0,0/pci8086,e08@3/pci1000,3020@0/iport@8
/pci@0,0/pci8086,e08@3/pci1000,3020@0/iport@8 (mpt_sas6) online
sd3 at mpt_sas6: unit-address w5000cca042003049,0: w5000cca042003049,0
sd3 is /pci@0,0/pci8086,e08@3/pci1000,3020@0/iport@8/disk@w5000cca042003049,0
/pci@0,0/pci8086,e08@3/pci1000,3020@0/iport@8/disk@w5000cca042003049,0 (sd3) online
npe2 at root: space 79 offset 0
npe2 is /pci@79,0
PCI Express-device: pci8086,e04@2, pcieb7
pcieb7 is /pci@79,0/pci8086,e04@2
PCIE-device: pci1000,3020@0, mpt_sas1
PCI Express-device: pci1000,3020@0, mpt_sas1
mpt_sas1 is /pci@79,0/pci8086,e04@2/pci1000,3020@0
mpt_sas19 at mpt_sas1: scsi-iport 80
mpt_sas19 is /pci@79,0/pci8086,e04@2/pci1000,3020@0/iport@80
/pci@79,0/pci8086,e04@2/pci1000,3020@0/iport@80 (mpt_sas19) online
sd15 at mpt_sas19: unit-address w5000cca042002fb9,0: w5000cca042002fb9,0
sd15 is /pci@79,0/pci8086,e04@2/pci1000,3020@0/iport@80/disk@w5000cca042002fb9,0
/pci@79,0/pci8086,e04@2/pci1000,3020@0/iport@80/disk@w5000cca042002fb9,0 (sd15) online
root on rpool/ROOT/solaris fstype zfs
...