cross-build: Include sys/types.h from sys/param.h

FreeBSD has a style(9) enforced assumption that sys/param.h includes
sys/types.h. However, Linux under musl doesn't do this so go ahead and
explicitly include it here. It won't hurt on the glibc systems, and
helps musl.

Co-authored-by: Val Packett <val@packett.cool>
Sponsored by: Netflix
Pull Request: https://github.com/freebsd/freebsd-src/pull/1066
Reviewed by: val_packett.cool
Differential Revision: https://reviews.freebsd.org/D45352