am33x-cm3: add FW for suspend/resume

Without this firmware, the beaglebone won't be able to reboot correctly.

Signed-off-by: Anders Darander <anders@chargestorm.se>
beaglebone: add am33x-cm3 to the build

Add the FW needed for the Cortex M3 on the beaglebone. This is required for
a working power management.

Signed-off-by: Anders Darander <anders@chargestorm.se>
beaglebone: enable NFS root

Signed-off-by: Anders Darander <anders@chargestorm.se>