Make kallsyms heuristics stricter so it doesn't get confused on older devices.

[ezdiy]

Fixes "confused" kallsyms on 4.14 / A10. This needs to be tested that it doesn't break newer kernels.

When kallsyms get "confused", we guess the offset of addresses/offsets wrong, and subsequently produce garbage kallsyms table. This then segfaults in page_init / other patches pointing to wrong (usually too large) address.

Potentially fixes #204, as they're getting segfault also (though it's not clear where).