perf script: Fix man page about --dump-raw-trace option

The "--dump-raw-script" is not a valid option, replace it with the valid
one, "--dump-raw-trace"

Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 133dc4c3 ("perf: Rename 'perf trace' to 'perf script'")
LPU-Reference: 728644547.14560155.1484320012612.JavaMail.zimbra@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>