tools/power cpupower: Show C0 in idle-info dump

tools/power cpupower: Show C0 in idle-info dump

`cpupower idle-info -o` skipped C0 because the loop began at 1:

  before:
    states:
      C1 ... latency[002] residency[00002]
      C2 ... latency[010] residency[00020]
      C3 ... latency[133] residency[00600]

  after:
    states:
      C0 ... latency[000] residency[00000]
      C1 ... latency[002] residency[00002]
      C2 ... latency[010] residency[00020]
      C3 ... latency[133] residency[00600]

Start iterating at index 0 so the idle report mirrors sysfs and
includes C0 stats.

Link: https://lore.kernel.org/r/20251202065403.1492807-1-kaushlendra.kumar@intel.com
Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>