perf report: Fix NULL pointer dereference in hists__fprintf_nr_sample_events()

The 'evname' variable can be NULL, as it is checked a few lines back,
check it before using.

Fixes: 9e207ddfa207 ("perf report: Show call graph from reference events")
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lore.kernel.org/lkml/
Signed-off-by: Gaurav Singh <[email protected]>

0 files changed, 0 insertions, 0 deletions