Fix return type of AO_int_X primitives defined in ao_t_is_int header

Fix return type of AO_int_X primitives defined in ao_t_is_int header

* src/atomic_ops/sysdeps/ao_t_is_int.h
(AO_int_fetch_compare_and_swap_full,
AO_int_fetch_compare_and_swap_acquire,
AO_int_fetch_compare_and_swap_release,
AO_int_fetch_compare_and_swap_write,
AO_int_fetch_compare_and_swap_read, AO_int_fetch_compare_and_swap,
AO_int_load_acquire, AO_int_fetch_and_add_full,
AO_int_fetch_and_add1_acquire, AO_int_fetch_and_add1_release,
AO_int_fetch_and_sub1_acquire, AO_int_fetch_and_sub1_release): Cast
result to unsigned int instead of signed int.