Use ttyAMA1

This allows raspi4b to boot. It fails while trying to mount a volume.

Keep in mind that the SSH authorized keys truncate the append, so
important cmdlines must be added here
```sh
cat <<EOF> mkosi.local.conf
[Host]
ExtraSearchPaths=build/
KernelCommandLine=earlycon=pl011,mmio32,0xfe201000 console=ttyAMA1 root=/dev/mmcblk1p2 rootdelay=1
EOF
```

```sh
sudo mkosi --machine $(uuidgen) --debug --qemu-firmware linux --qemu-kernel kernel8.img --qemu-kvm=false --qemu-swtpm=false --qemu-smp 4 --runtime-scratch=false qemu -machine raspi4b -dtb bcm2711.dtb
```

Signed-off-by: Anne Isabelle "Anya" Macedo <annie@retpolanne.com>

mkosi/config.py

@@ -449,8 +449,8 @@ def to_oci(self) -> str:
 
     def default_serial_tty(self) -> str:
         return {
-            Architecture.arm      : "ttyAMA0",
-            Architecture.arm64    : "ttyAMA0",
+            Architecture.arm      : "ttyAMA1",
+            Architecture.arm64    : "ttyAMA1",
             Architecture.s390     : "ttysclp0",
             Architecture.s390x    : "ttysclp0",
             Architecture.ppc      : "hvc0",