cpu: fix NumberFormatException in live oc/uc

Could be caused by overclocking or simply by wrong user input.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>
boot: fix force close when overclocked

Just a wrong cast operation could crash anything.
Now doing this really save, so no more fc's should be
expected.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>