perf tools: Cast off_t to s64 to avoid warning on bionic libc

perf tools: Cast off_t to s64 to avoid warning on bionic libc

To avoid this warning:

    CC       /tmp/build/perf/util/s390-cpumsf.o
  util/s390-cpumsf.c: In function 's390_cpumsf_samples':
  util/s390-cpumsf.c:508:3: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 4 has type 'off_t' [-Wformat=]
     pr_err("[%#08" PRIx64 "] Invalid AUX trailer entry TOD clock base\n",
     ^

Now the various Android cross toolchains used in the perf tools
container test builds are all clean and we can remove this:

  export EXTRA_MAKE_ARGS="WERROR=0"

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lkml.kernel.org/n/tip-5rav4ccyb0sjciysz2i4p3sx@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>