Hide or namespace the remaining tracepoint internal symbols

Hide or namespace the remaining tracepoint internal symbols

The major SONAME bump to '1' gives us the opportunity to hide private
symbols that should never have been visible.

Namespace the symbols that are part of the liblttng-ust-tracepoint ABI
but are not part of the public API.

Change-Id: I46125715e88f88891fe0c02a95adbbf6792a33e2
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>