ArmPkg/CompilerIntrinsicsLib: provide atomics intrinsics

ArmPkg/CompilerIntrinsicsLib: provide atomics intrinsics

Gary reports the GCC 10 will emit calls to atomics intrinsics routines
unless -mno-outline-atomics is specified. This means GCC-10 introduces
new intrinsics, and even though it would be possible to work around this
by specifying the command line option, this would require a new GCC10
toolchain profile to be created, which we prefer to avoid.

So instead, add the new intrinsics to our library so they are provided
when necessary.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Tested-by: Gary Lin <glin@suse.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>