sd-image-aarch64.nix: Document serial ports used

Also drop boot.consoleLogLevel which already comes from
installation-device.nix

Changed files
+6 -3
nixos
modules
installer
+6 -3
nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
···
boot.loader.generic-extlinux-compatible.enable = true;
boot.kernelPackages = pkgs.linuxPackages_latest;
-
# Increase the amount of CMA to ensure the virtual console on the RPi3 works.
-
boot.kernelParams = ["cma=32M" "console=ttyS0,115200n8" "console=tty0"];
-
boot.consoleLogLevel = 7;
+
+
# The serial ports listed here are:
+
# - ttyS0: for Tegra (Jetson TX1)
+
# - ttyAMA0: for QEMU's -machine virt
+
# Also increase the amount of CMA to ensure the virtual console on the RPi3 works.
+
boot.kernelParams = ["cma=32M" "console=ttyS0,115200n8" "console=ttyAMA0,115200n8" "console=tty0"];
# FIXME: this probably should be in installation-device.nix
users.extraUsers.root.initialHashedPassword = "";