Fix two mismatches between function declaration and definition.

In both cases, function pointer arguments were inconsistently declared
and the result worked because of C's odd rules around function pointer
(de)references. With a stricter compiler these fail to compile.

Reviewed by: cem
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D20964