CVE-2026-68378 dpll: fix NULL pointer dereference in dpll_msg_add_pin_ref_sync()

In the Linux kernel, the following vulnerability has been resolved: dpll: fix NULL pointer dereference in dpllmsgaddpinrefsync When a dpllpin is shared across multiple dplldevice instances and those devices are being unregistered e.g. during driver module removal, a NULL pointer dereference can...