vBSP430lpmConfigurePortsForLPM_ni corrupts initial console output

[pabigot]

On exp430fr5739 and trxeb if vBSP430lpmConfigurePortsForLPM_ni() is invoked before vBSP430platformInitialize_ni() the UART is unstable for the first several characters.

[pabigot]

Note that both of these platforms use the ti-usb ACM serial interface. The issue does not appear on the exp430f5438.