SUNRPC: Export enums in tracepoints to user space

The enums used in the tracepoints for __print_symbolic() have their
names shown in the tracepoint format files. User space tools do not know
how to convert those names into their values to be able to convert the
binary data.

Use TRACE_DEFINE_ENUM() to export the enum names to their values for
userspace to do the parsing correctly.

Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org



Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>