kernel: Add defination of .init_array and .fini_array for all other platforms

Currently these sections are not used but defined only for amd64 and
i386. Added them for all other platforms to keep all platforms in sync.
There should be no functional change.

This change is extracted from a bigger patch [1] of hselasky, with
additional fix for the order of .fini_array section.

1. https://reviews.freebsd.org/D40467

Obtained from: hselasky
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D45214

(cherry picked from commit 3e76d05231b0aa77d922bdbc9abf62d9747a91ab)