perf tools: Use %zd for size_t printf formats on 32-bit

A couple of trivial fixes for using %zd for size_t in the code
supporting the ZSTD compression library.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200820212501.24421-1-chris@chris-wilson.co.uk


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>