Generate generalized AO_t load/store/fetch_and_add primitives from template

Generate generalized AO_t load/store/fetch_and_add primitives from template
(code refactoring)

* src/Makefile.am (atomic_ops/generalize-small.h): Append
generalize-small.template to generalize-small.h replacing XCTYPE with
AO_t (and "XSIZE_" with empty sequence).
* src/atomic_ops/generalize-small.h: Regenerate.
* src/atomic_ops/generalize.h (AO_load_acquire, AO_load, AO_load_read,
AO_load_acquire_read, AO_load_full, AO_load_dd_acquire_read,
AO_store_release, AO_store, AO_store_write, AO_store_release_write,
AO_store_full, AO_fetch_and_add_full, AO_fetch_and_add_acquire,
AO_fetch_and_add_release, AO_fetch_and_add, AO_fetch_and_add_write,
AO_fetch_and_add_read, AO_fetch_and_add_release_write,
AO_fetch_and_add_acquire_read, AO_fetch_and_add_dd_acquire_read,
AO_fetch_and_add1_full, AO_fetch_and_add1_release,
AO_fetch_and_add1_acquire, AO_fetch_and_add1_write,
AO_fetch_and_add1_read, AO_fetch_and_add1_release_write,
AO_fetch_and_add1_acquire_read, AO_fetch_and_add1,
AO_fetch_and_add1_dd_acquire_read, AO_fetch_and_sub1_full,
AO_fetch_and_sub1_release, AO_fetch_and_sub1_acquire,
AO_fetch_and_sub1_write, AO_fetch_and_sub1_read,
AO_fetch_and_sub1_release_write, AO_fetch_and_sub1_acquire_read,
AO_fetch_and_sub1, AO_fetch_and_sub1_dd_acquire_read): Remove
generalized primitives (and the corresponding AO_HAVE_x macros) that
exist in auto-generated generalize-small.h file.