make ktap reentrant

This patch make ktap reentrant, it don't disable irq in
callback function, same as perf and ftrace.

To make reentrant, we need some percpu data to be
context isolation(irq/sirq/nmi/process)

perf callback already consider on the recursion issue,
so ktap don't need to check again in here,
but need to care on one case:
 callback invoked in timer expired path
(this issue will be address soon)