ANDROID: Unconditionally create bridge tracepoints

Even if the bridge module is not enabled, we may need the tracepoints
downstream in products that enable bridge.ko, so avoid defining the
export of these symbols based on a config option.

Bug: 150625937
Change-Id: Ib961fd6e353fe3bdfde11a38488568f42f1dbe7a
Signed-off-by: Alistair Delva <adelva@google.com>