mISDN: fix possible memory leak in mISDNdspelement_register()
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 v5.4.225 by commit 0f2c681900a01e3f23789bca26d88268c3d5b51d, it was introduced in version v2.6.30 by commit 1fa5ae857bb14f6046205171d98506d8112dd74e. For more details please see the references link.