tracing/osnoise: Fix compile warning in function start_kthread

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4G64B


CVE: NA

-------------------------------------------------

This patch fixes following compile warning:

---------------------- [WARNING] checkbuild_arm64 ----------------------

build warning: arm64, allmodconfig

kernel/trace/trace_osnoise.c: In function ‘start_kthread’:
kernel/trace/trace_osnoise.c:1674:8: warning: ‘main’ is usually a function [-Wmain]
  void *main = osnoise_main;
        ^~~~
---------------------- [WARNING] checkbuild_x86_64 ----------------------

build warning: x86_64, allmodconfig

kernel/trace/trace_osnoise.c: In function ‘start_kthread’:
kernel/trace/trace_osnoise.c:1674:8: warning: ‘main’ is usually a function [-Wmain]
  void *main = osnoise_main;
        ^~~~

Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>