Add utility functions to convert uints to bytes

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add a function to erase the memory of the OSTC3

This is the fist step in the firmware upgrade process.

This code is party based on bits from JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add function to read the rom from the OSTC3

This is necessary to verify that the memory written got transfered
correctly.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add code to write rom of the OSTC3

This is now you transfer a new firmware to the OSTC3.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add a function upgrade the firmware in the OSTC3

This function triggers a reboot into the bootloader which flashes the
new firmware to Prom.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Firmware upgrade for OSTC3

This connects the bits and implements firmware upgrade for the OSTC3.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Teach examples/ostc-fwupdate about OSTC3

This teaches the example firmware upgrader about how to upgrade the
OSTC3's.

Signed-off-by: Anton Lundin <glance@acc.umu.se>