Processor.java: Fixes and Cleanups

1: Fix issue where Processor settings FC whenever one of the /sys/devices/system/cpu/cpu0/cpufreq/* files is missing.
2: Cleanup for better overview.
3: No need to add empty content to disabled/removed elements.
4: Do not start the current cpu freq loop if the files needed are missing.
5: Also add the check for missing or empty files in the 'onResume' part.
6: Disable elements with missing files rather than remove them to maintain the layout.

Change-Id: Ib0cc3b01cbce368e23530760e2d87eedd04ad10a