gpu: fix force close while casting class

Somehow it seems our custom preferences still go through
the onClick event even if set to onChange.
Handle this properly fixes those strange force closes.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>
helpers: fix wired race conditions once and for all

Just let the thread sleep for two full seconds, so the
kernel and filesystem can catch up and create the new
files.

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