perf tools: Move parse_nsec_time to time-utils.c

perf tools: Move parse_nsec_time to time-utils.c

Code move only; no functional change intended.

Committer notes:

Fix the build on Ubuntu 16.04 x86-64 cross-compiling to S/390, with this
set of auto-detected features:

  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  ...                          gtk2: [ OFF ]
  ...                      libaudit: [ OFF ]
  ...                        libbfd: [ OFF ]
  ...                        libelf: [ on  ]
  ...                       libnuma: [ OFF ]
  ...        numa_num_possible_cpus: [ OFF ]
  ...                       libperl: [ OFF ]
  ...                     libpython: [ OFF ]
  ...                      libslang: [ OFF ]
  ...                     libcrypto: [ OFF ]
  ...                     libunwind: [ OFF ]
  ...            libdw-dwarf-unwind: [ on  ]
  ...                          zlib: [ on  ]
  ...                          lzma: [ OFF ]
  ...                     get_cpuid: [ OFF ]
  ...                           bpf: [ on  ]

Where it was failing with:

    CC       /tmp/build/perf/util/time-utils.o
  util/time-utils.c: In function 'parse_nsec_time':
  util/time-utils.c:17:13: error: implicit declaration of function 'strtoul' [-Werror=implicit-function-declaration]
    time_sec = strtoul(str, &end, 10);
               ^
  util/time-utils.c:17:2: error: nested extern declaration of 'strtoul' [-Werror=nested-externs]
    time_sec = strtoul(str, &end, 10);
    ^
  util/time-utils.c: In function 'perf_time__parse_str':
  util/time-utils.c:93:2: error: implicit declaration of function 'free' [-Werror=implicit-function-declaration]
    free(str);
    ^
  util/time-utils.c:93:2: error: incompatible implicit declaration of built-in function 'free' [-Werror]
  util/time-utils.c:93:2: note: include '<stdlib.h>' or provide a declaration of 'free'

Do as suggested and add a '#include <stdlib.h>' to get the free() and strtoul()
declarations and fix the build.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1480439746-42695-3-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>