Fix the signature for zone_import and zone_release

[andrew]

Summary

These are cast to uma_import and uma_release functions. Use the signature
for these in the zone fucntions.

This was found with an experimental Kernel CFI. It will complaid if the
signature is different than what a function pointer expects. The
simplest way to fix these is to correct the signature.

[rlibby]

Looks fine.

Is this going to identify all casting of function pointers? These ones
here seem pretty innocuous.

[andrew]

It will find all pointers that are used, however I exclude a few functions that may call different, but compatible types e.g. SYSINITS should be void func(const void *), but many don't include the const so I mark mi_startup with a no-cfi attribute.