Revert r327823, Enable ld.lld as bootstrap linker by default on i386

There's a report of some regression in ports. Revert for now for an
exp run for this change in isolation (previous lld exp run also included
switching the linker used for ports to lld).

Also revert the src.conf.5 regeneration in r327824.

Reported by: antoine
Sponsored by: The FreeBSD Foundation