selftests/mlock2: add ULL suffix to 64-bit constants

On 32-bit (e.g. m68k):

    mlock2-tests.c: In function 'lock_check':
    mlock2-tests.c:293: warning: integer constant is too large for 'long' type
    mlock2-tests.c:294: warning: integer constant is too large for 'long' type
    mlock2-tests.c:299: warning: integer constant is too large for 'long' type
    ...

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Eric B Munson <emunson@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>