kasan: move boot parameters section in documentation

kasan: move boot parameters section in documentation

Move the "Boot parameters" section in KASAN documentation next to the
section that describes KASAN build options.

No content changes.

Link: https://lkml.kernel.org/r/870628e1293b4f44edf7cbcb92374ff9eb7503d7.1652203271.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/ec9c923f35e7c5312836c4624a7f317dc1ee2c1c.1652123204.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>