ftrace: Fix some W=1 warnings in kernel doc comments

ftrace: Fix some W=1 warnings in kernel doc comments

Clean up the following clang-w1 warning:

kernel/trace/ftrace.c:7827: warning: Function parameter or member 'ops'
not described in 'unregister_ftrace_function'.

kernel/trace/ftrace.c:7805: warning: Function parameter or member 'ops'
not described in 'register_ftrace_function'.

Link: https://lkml.kernel.org/r/20220307004303.26399-1-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>