Correct the number of targets vs number of LUNs

Correct the number of targets vs number of LUNs

jsg@ has found out that the number of targets wasn't correct and
it turns out that the device supports up to 2 targets and 1 or 64
LUNs depending on whether it's taking over an IDE device or is a
virtual SCSI.

While here make sure the command response is copied back only for
synchronous commands that are issued during initialization phase.