support -F(use_ftrace_rb) option in ktap

Currently don't support reader in ktapio, so you still need use command
cat /sys/kernel/debug/tracing/trace_pipe
to get ktap output, It will be fix soon.

This patch also rename struct ktap_user_parm to ktap_parm.

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>