tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints

tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints

Register/unregister tracepoint probes with struct tracepoint pointer
rather than tracepoint name.

This change, which vastly simplifies tracepoint.c, has been proposed by
Steven Rostedt. It also removes 8.8kB (mostly of text) to the vmlinux
size.

From this point on, the tracers need to pass a struct tracepoint pointer
to probe register/unregister. A probe can now only be connected to a
tracepoint that exists. Moreover, tracers are responsible for
unregistering the probe before the module containing its associated
tracepoint is unloaded.

   text    data     bss     dec     hex filename
10443444        4282528 10391552        25117524        17f4354 vmlinux.orig
10434930        4282848 10391552        25109330        17f2352 vmlinux

Link: http://lkml.kernel.org/r/[email protected]
CC: Ingo Molnar <[email protected]>
CC: Frederic Weisbecker <[email protected]>
CC: Andrew Morton <[email protected]>
CC: Frank Ch. Eigler <[email protected]>
CC: Johannes Berg <[email protected]>
Signed-off-by: Mathieu Desnoyers <[email protected]>
[ SDR - fixed return val in void func in tracepoint_module_going() ]
Signed-off-by: Steven Rostedt <[email protected]>