do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

Fix a bug in mm/mlock.c on 32-bit architectures that prevents a user from
locking more than 4GB of shared memory, or allocating more than 4GB of
shared memory in hugepages, when rlim[RLIMIT_MEMLOCK] is set to
RLIM_INFINITY.

Signed-off-by: Herbert van den Bergh <[email protected]>
Acked-by: Chris Mason <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>