ideapad_laptop: Introduce the use of the managed version of kzalloc
This patch moves data allocated using kzalloc to managed data allocated
using devm_kzalloc and cleans now unnecessary kfrees in probe and remove
functions. The label sysfs_failed is removed as it is no longer
required. Also, linux/device.h is added to make sure the devm_*()
routine declarations are unambiguously available.
The following Coccinelle semantic patch was used for making the change: