v4l: Export enums used by tracepoints to user space

v4l: Export enums used by tracepoints to user space

Enums used by tracepoints for __print_symbolic() are shown in the
tracepoint format files with just their names and not their values.
This makes it difficult for user space tools to know how to convert the
binary data into their string representations.

By adding the use of TRACE_DEFINE_ENUM(), the enum names will be mapped
to their values and shown in the tracing file system to let tools
convert the data as necessary.

Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.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>