This is mainly a naming convention thing, we want to have 'isr'
as part of the name, instead of 'int'. We also want port_2 instead
of p2 because we already had port_1
See Pull Request #18
The P2 Interrupt is shared across many periferal (I2C, USB, GPIO).
This adds a generic interrupt handler on which the differents drivers
can register a handler.
See Pull Request #18
