perf tools: Handle print concatenations in event format file

kmem_alloc ftrace event format had a string that was broken up
by two tokens. "string 1" "string 2". This patch lets the parser
be able to handle the concatenation.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091014194357.253818714@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>