mm:kasan: fix sparse warnings: Should it be static?

mm:kasan: fix sparse warnings: Should it be static?

Yes, when making the global variables kasan_ptr_result and
kasan_int_result as static volatile, the warnings are removed and the
variable and assignments are retained, but when just static is used I
understand that it might be optimized.

Add a fix making the global varaibles - static volatile, removing the
warnings:
mm/kasan/kasan_test.c:36:6: warning: symbol 'kasan_ptr_result' was not declared. Should it be static?
mm/kasan/kasan_test.c:37:5: warning: symbol 'kasan_int_result' was not declared. Should it be static?

Link: https://lkml.kernel.org/r/20241011114537.35664-1-niharchaithanya@gmail.com
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312261010.o0lRiI9b-lkp@intel.com/
Signed-off-by: Nihar Chaithanya <niharchaithanya@gmail.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>