UPSTREAM: Revert "x86_64: Increase stack size for KASAN_EXTRA"

(Upstream commit a2863b53418d7d8f6332adf0cfb32611def0c4b9).

This reverts commit a8e911d13540487942d53137c156bd7707f66e5d.
KASAN_EXTRA was removed via the commit 7771bdbbfd3d ("kasan: remove use
after scope bugs detection."), so this is no longer needed.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: bp@alien8.de
Cc: akpm@linux-foundation.org
Cc: aryabinin@virtuozzo.com
Cc: glider@google.com
Cc: dvyukov@google.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20190306213806.46139-1-cai@lca.pw


Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Bug: 128674696
Change-Id: I81cae91b45c69906239518da0965a139112ccfe2