built-in.o were introduced in top-level Makefile to saves us from
linking the same .o files several times when kallsyms were enabled.
Unfortunately this caused a hard lock-up on x86_64 - so this patch drops
built-in.o again. Please note is was working on i386.

This patch also fixes some wording/spellings noticed by: Horst von Brand <vonbrand@inf.utfsm.cl>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>