perf intel-pt: Allow decoding with branch tracing disabled

perf intel-pt: Allow decoding with branch tracing disabled

The kernel now supports the disabling of branch tracing, however the
decoder assumes branch tracing is always enabled. Pass through a parameter
to indicate whether branch tracing is enabled and use it to avoid cases
when the decoder is expecting branch packets. There are 2 such cases.
First, FUP packets which can bind to an IP even when there is no branch
tracing. Secondly, the decoder will try to use branch packets to find an IP
to start decoding or to recover from errors.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-11-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>