In general eTPU2 can run at 200MHz at most.
eTPU on MPC5644A can run at 150MHz when configured for full system clock. Note that eTPU graphical configuration tool use maximum value 145MHz, but qualified device is capable to achieve 150MHz. It is needed to edit c:\Program Files (x86)\Freescale\eTPU Graphical Configuration Tool\conf\etpucpu.ini and fix max system clock for MPC5644A to 150MHz:
[MPC5644A]
module=eTPU2
engines=1
system_clock=150
etpu_clk_prescaler=1
STAC_bus_available=Yes
template=template_MPC5644A