perf tools: Fix bprintk reading in trace output

The bprintk parsing was broken in more ways than one.

The file parsing was incorrect, and the words used by the
arguments are always 4 bytes aligned, even on 64-bit machines.

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: <20091014194359.520931637@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>