acer-wmi: double free in acer_rfkill_exit()

This is acer_rfkill_exit() from drivers/platform/x86/acer-wmi.c.

The code frees wireless_rfkill->data again instead of
bluetooth_rfkill->data.

This was found using a code checker (http://repo.or.cz/w/smatch.git/).

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: Len Brown <len.brown@intel.com>