Set the parentDetect flag to NOT_WR_PARENT only if we think
that the parent is WR_PARENT, i.e. thsi flag is not set in
case that parentDetection=PD_NO_DETECTION because that means
we already know whether we are speaking with WR guy or not.
Previously, this condition was parentDetection!=PD_NOT_WR_PARENT
and there was some trashing when WR slave port was speaking
to nonWR port. This is because parentDetection=PD_NO_DETECTION
was set and then parentDetection=PD_NOT_WR_PARENT was re-set
which cause the slave to go back to UNCALIBRATED from SLAVE.