tracing: Show size of requested perf buffer

commit a90afe8d

 upstream.

If the perf buffer isn't large enough, provide a hint about how large it
needs to be for whatever is running.

Link: https://lkml.kernel.org/r/20210831043723.13481-1-robbat2@gentoo.org

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>