Change either RTM_PS# or EN_I2C_RTM pins on LPC so one can be output while the other is an input
We can't use one for data input and the other for output, since they are
the USB pins, the LPC17xx hardware doesn't let them have different
directions, they must be either inputs or outputs at the same time.
This is an inconvenience for us, since P0.29 is connected to the
RTM_PS# input signal and P0.30 is the EN_I2C_RTM output, so we have
to multiplex these pin directions in the firmware, which is not the
optimal solution