stm class: ftrace: Use different channel accroding to CPU

stm class: ftrace: Use different channel accroding to CPU

To avoid mixup of packets from differnt ftrace packets simultaneously,
use different channel for packets from different CPU.

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20201005071319.78508-7-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>