perf bench: Fix 2 memory sanitizer warnings

perf bench: Fix 2 memory sanitizer warnings

Memory sanitizer warns if a write is performed where the memory being
read for the write is uninitialized. Avoid this warning by initializing
the memory.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200912053725.1405857-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[sw0312.kim: backport upstream commit d2c73501a767 to resolve gcc-12 build issue]
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: I5ddf75c23c88777a9cee798d72605533d3a7f318