arm64: do not trace atomic operations

Atomic operation function symbols are exported,when
CONFIG_ARM64_LSE_ATOMICS is defined. Prefix them with notrace, so that
an user can not trace these functions. Tracing these functions causes
kernel crash.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>