> do i need to clock the eTSEC clock input as well - ?
No - refer to the P2020 QorIQ Integrated Processor Reference Manual, Table 14-1. eTSECn network interface signal properties:
"EC _GTX_CLK125
Oscillator source for GMII, TBI, RGMII, RTBI transmit clock, input, shared by all eTSECs"