The "acpi_idle_do_entry", "acpi_processor_ffh_cstate_enter", and
"idle_cpu" symbols appear in 'perf top' output, at least on AMD systems.

Add them to perf's idle_symbols list, so they don't dominate 'perf top'
output.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200207230613.26709-2-kim.phillips@amd.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>