My work-in-progress -Wincompatible-function-pointer-types-strict Clang warning found ~30 more type mismatches in function pointer assignments, which we should look into fixing.

There are roughly the same number of warnings for both x86_64 and arm64 allmodconfigs, mostly duplicates, except for an arch-specific driver or two. All the warnings seem to be automatic integer <-> enum conversions, similar to issue #1703, each of which could potentially trip CFI checking.

cc @kees @nathanchance @GustavoARSilva