The spinlock implementation is unfair, some threads may take locks
aggressively while leaving the other threads starving for long time.
This patch introduces ticketlock which gives each waiting thread a
ticket and they can take the lock one by one. First come, first serviced.
This avoids starvation for too long time and is more predictable.
Suggested-by: Jerin Jacob <jerinj@marvell.com> Signed-off-by: Joyce Kong <joyce.kong@arm.com> Reviewed-by: Gavin Hu <gavin.hu@arm.com> Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>