Use AO_ prefix for internal functions in arm_v6.h
(code refactoring)

* src/atomic_ops/sysdeps/armcc/arm_v6.h (AO_fetch_and_add,
AO_fetch_and_add1, AO_fetch_and_sub1, AO_compare_and_swap): Remove
useless comment.
* src/atomic_ops/sysdeps/armcc/arm_v6.h (load_ex, store_ex): Add
"AO_" prefix.
Fix AO_XSIZE_load/store definition order in generalize-small template

* src/atomic_ops/generalize-small.template (AO_XSIZE_load): Move
definition (which is based on AO_XSIZE_load_acquire) down to be after
AO_XSIZE_load_acquire definition.
* src/atomic_ops/generalize-small.template (AO_XSIZE_store): Move
definition (which is based on AO_XSIZE_store_release) down to be after
AO_XSIZE_store_release definition.
* src/atomic_ops/generalize-small.h : Regenerate.
Fix generalize-small template adding missed CAS-based fetch_and_add

* src/atomic_ops/generalize-small.template (AO_XSIZE_fetch_and_add):
Add missed definition based on CAS.
* src/atomic_ops/generalize-small.h: Regenerate.
Move 'unsigned' keyword to XCTYPE in generalize-small template
(code refactoring)

* src/Makefile.am (atomic_ops/generalize-small.h): Add trailing '_'
to XSIZE and to its replacement; add "unsigned" prefix to the types
replacing XCTYPE (using empty comment as a delimiter between
"unsigned" keyword and char/short).
* src/atomic_ops/generalize-small.template: Remove "unsigned" keyword
at every XCTYPE.
* src/atomic_ops/generalize-small.h: Regenerate.
Add missing generalization of no-barrier CAS in template

* src/atomic_ops/generalize-small.template
(AO_XSIZE_compare_and_swap): Add missed definition (based on
AO_XSIZE_fetch_compare_and_swap).
* src/atomic_ops/generalize-small.template
(AO_XSIZE_fetch_and_add_full): Add comment (copy from generalize.h).
* src/atomic_ops/generalize-small.h: Regenerate.