feat(lib): add 8-bit atomic primitives

Add 8-bit atomic inline functions
- atomic_load_add_8()
- atomic_load_add_release_8()
- atomic_eor_8()
and macros
- SCA_READ8()
- SCA_READ8_ACQUIRE()
for aarch64 and host platforms.

Change-Id: Ibb78f4b70d98d5a820431b063055ebd484a95f7e
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
4 files changed