android-boot: Only add the device if updatable
android-boot: Only add the device if updatable

Otherwise we get devices like:

    ├─EFI\x20system\x20partition:
    │     Device ID:          003a0352e13dc2defe8548eb541d56067e5e5d71
    │     Summary:            Android Bootloader
    │     Current version:    0.0.0
    │     GUIDs:              a4001789-0ca9-5f4c-8c53-e65f8ec8a825
    │                         9d825eae-ef58-501c-944f-6a0a8d9cfb49
    │     Device Flags:       • Internal device
    │                         • System requires external power source
    │                         • Needs a reboot after installation
    │                         • Cryptographic hash verification is available

fwupd/fwupd,fwupd/fwupd,fwupd/fwupd,fwupd/fwupd