tools/power/x86/intel-speed-select: Ignore missing config level

It is possible that certain config levels are not available, even
if the max level includes the level. There can be missing levels in
some platforms. So ignore the level when called for information dump
for all levels and fail if specifically ask for the missing level.

Here the changes is to continue reading information about other levels
even if we fail to get information for the current level. But use the
"processed" flag to indicate the failure. When the "processed" flag is
not set, don't dump information about that level.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>