The recording of the names at trace time is inefficient. This patch
implements the softirq event recording to only record the vector
and then use the __print_symbolic interface to print out the names.

[ Impact: faster recording of softirq events ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>