ice(4): Add support for 40G maximal PMD speed

E823 backplane devices may support 40G as maximal PMD speed.
Extend port topology reading logic to handle this case.
While at that fix indentation according to FreeBSD style(9).

Signed-off-by: Krzysztof Galazka <krzysztof.galazka@intel.com>

Tested by: gowtham.kumar.ks_intel.com
Approved by: kbowling (mentor), erj (mentor)
Sponsored by: Intel Corporation
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D53587