Kconfig.debug: ensure early check for KMSAN in CONFIG_KMSAN_WARN

As pointed out by Masahiro Yamada, Kconfig picks up the first default
entry which has true 'if' condition.  Hence, the previously added check
for KMSAN was never used, because it followed the checks for 64BIT and
!64BIT.

Put KMSAN check before others to ensure it is always applied.

Link: https://lkml.kernel.org/r/20221102110611.1085175-3-glider@google.com
Link: https://github.com/google/kmsan/issues/89
Link: https://lore.kernel.org/linux-mm/20221024212144.2852069-3-glider@google.com/
Fixes: 921757bc

 ("Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default")
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>