tools/include: Update atomic definitions

Add atomic_long_set function to atomic.h and atomic_long_t type to
types.h so they can be used in testing.

Signed-off-by: Karolina Drobnik <karolinadrobnik@gmail.com>
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Link: https://lore.kernel.org/r/082fde69debc36bfc56cdb413d847dcd6b1e36dd.1643796665.git.karolinadrobnik@gmail.com