iflib: Fix white space and reduce some line lengths

This helps align some of the code with the rest of the style used in
iflib, but as marius@ points out, this is not style(9).

Signed-off-by: Eric Joyner <erj@FreeBSD.org>

Reviewed by: kbowling@
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D41324

(cherry picked from commit 7f527d48124bd03fcfb946ce2d5d0c7bc71e099d)