tools/power turbostat: fix goldmont C-state limit decoding

[ Upstream commit 445640a563493f28d15f47e151e671281101e7dc ]

When the C-state limit is 8 on Goldmont, PC10 is enabled.
Previously turbostat saw this as "undefined", and thus assumed
it should not show some counters, such as pc3, pc6, pc7.

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>