created a copy of the board "overo" to "overo_pengupilot"
use:
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- omap3_overo_pengupilot_config
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- all

the difference is, that is sets mode 4 for the MMC3 lines, thus allowing
you to use all the lines as GPIOs