gcore: Trim stale bits from elf32core.c.

These should have been removed in
d95657a1a758e8d993a0eb92259f8c860a309207.

Reviewed by: markj
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D35748

(cherry picked from commit a6c3e5fa39a01d63d18b24d9afabfc95c734650e)