tracing: Add needs_rec flag to event triggers

tracing: Add needs_rec flag to event triggers

Add a new needs_rec flag for triggers that require unconditional
access to trace records in order to function.

Normally a trigger requires access to the contents of a trace record
only if it has a filter associated with it (since filters need the
contents of a record in order to make a filtering decision).  Some
types of triggers, such as 'hist' triggers, require access to trace
record contents independent of the presence of filters, so add a new
flag for those triggers.

Link: http://lkml.kernel.org/r/7be8fa38f9b90fdb6c47ca0f98d20a07b9fd512b.1449767187.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>