refactor(rpi): split out console registration logic

Detection of the UART in use and GPIO code only apply to RPi 3 and 4.

RPi 5 has a dedicated PL011 debug port.

Change-Id: Iddf8aea01278e2b79b4e7c476740f1add8c419f0
Signed-off-by: Mario Bălănică <mariobalanica02@gmail.com>
6 files changed