Greenpak4ClockBuffer: added GetBufferNumber()
Greenpak4ClockBuffer: added GetBufferNumber()

azonenberg/openfpga,rqou/openfpga,azonenberg/openfpga,rqou/openfpga,rqou/openfpga,azonenberg/openfpga,rqou/openfpga,azonenberg/openfpga,azonenberg/openfpga,rqou/openfpga