perf timechart: Remove the unused use_old_power_events variable

It is set once and never read: its only reader went away in
20c457b8587bee46 ("perf timechart: Adjust perf timechart to the new power
events") and nothing used it since, so the assignment was dead code for
13 years.

clang 23 extends -Wunused-but-set-variable to file-scope variables with
internal linkage, under the new -Wunused-but-set-global subgroup, and
with the -Werror that perf uses by default that turns the dead
assignment into a build error:

  builtin-timechart.c:355:12: error: variable 'use_old_power_events' set but not used
      [-Werror,-Wunused-but-set-global]

as seen building with clang 23.1.1 on Fedora 45 and rawhide, where gcc,
older clang and clang without -Werror all keep building it.

Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: LLM
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0 files changed, 0 insertions, 0 deletions