make kconfig_check arch-specific to support CONFIG_LBDAF

Created by: ollieparanoid

The kconfig option LBDAF is required to mount ext4 partitions (unless they have been created with non-default settings). But that option is only present in 32 bit (armhf, x86), not 64 bit (aarch64, x86_64) kernels. So if we added it to kconfig_check right now, it would incorrectly report the 64 bit device's kernels to be missing that option.

@MartijnBraam pointed out in #postmarketOS, that we could make the options we check for arch specific to resolve this.

The options we are checking for are defined in pmb/config/__init__.py:

necessary_kconfig_options = {
    "ANDROID_PARANOID_NETWORK": False,
    "DEVTMPFS": True,
    ...
}

One approach would be to group these options:

necessary_kconfig_options = {
    "all": {"ANDROID_PARANOID_NETWORK": False,
            "DEVTMPFS": True, ...},
    "armhf x86": {"LBDAF": True}
}