perf intel-pt: Fix sync state when a PSB (synchronization) packet is found

perf intel-pt: Fix sync state when a PSB (synchronization) packet is found

When syncing, it may be that branch packet generation is not enabled at
that point, in which case there will not immediately be a control-flow
packet, so some packets before a control flow packet turns up, get
ignored.  However, the decoder is in sync as soon as a PSB is found, so
the state should be set accordingly.

Fixes: 8511b3d29c2c12 ("perf tools: Add Intel PT decoder")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v5.15+
Link: https://lore.kernel.org/r/20211210162303.2288710-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>