Remove deps on non-freely accessible code.
Due to licensing concerns, we cannot use any of the code in the "support" folder of the EDISOFT compiler. After doing some tests, it seems that the only pieces of that code that we depended on were the ones used to perform output to the serial port. This set of changes:
- Provides a minimal implementation of outputing a character on the leon2's first serial port
- Patches mphalport to delegate to this function.
- Removes the dependencies on the support/ folder from the relevant Makefiles