tools/metrics.py: Add rp2 port to table of ports that can be built.
tools/metrics.py: Add rp2 port to table of ports that can be built.

Signed-off-by: Damien George <99e6b749acbfbe2a596df99e91d24d6e1fdbee00@micropython.org>

bvernoux/micropython,henriknelson/micropython,bvernoux/micropython,bvernoux/micropython,henriknelson/micropython,henriknelson/micropython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython,adafruit/circuitpython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython,bvernoux/micropython