contrib: add ttyS0 to list of ttys to start in Alpine Linux
# Consoles to start getty on when system is up
+tty [12345] /dev/ttyS0 noclear
tty [12345] /dev/tty1 noclear nowait
tty [2345] /dev/tty2 noclear nowait
tty [2345] /dev/tty3 noclear nowait
