perf intel-pt: Remove a check for sampling mode

perf intel-pt: Remove a check for sampling mode

Intel PT code already has some preparation for AUX area sampling mode.

However the implementation has changed from the first proposal and one
of the side-effects is that it will not be impossible to support snapshot
mode and sampling mode at the same time.

Although there are no plans to support it, let validation (not yet
implemented) control whether it is allowed rather than low-level
functions.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1520431349-30689-9-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>