regmap: Fix possible double-free in regcacherbtreeexit()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v4.4.291 by commit e72dce9afbdbfa70d9b44f5908a50ff6c4858999, it was introduced in version v3.12 by commit 3f4ff561bc88b074d5e868dde4012d89cbb06c87. For more details please see the references link.