Implement XADD eBPF instruction using STADD arm64 instruction.
If the given platform does not have atomics support,
use LDXR and STXR pair for critical section instead of STADD.
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>