Revert "x86/build: Move _etext to actual end of .text"

This reverts commit 392bef70.

It seems to cause lots of problems when using the gold linker, and no
one really needs this at the moment, so just revert it from the stable
trees.

Cc: Sami Tolvanen <samitolvanen@google.com>
Reported-by: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Alec Ari <neotheuser@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>