platform/chrome: cros_ec_typec: Init mutex in Thunderbolt registration

In the Linux kernel, the following vulnerability has been resolved: platform/chrome: cros_ec_typec: Init mutex in Thunderbolt registration cros_typec_register_thunderbolt() missed initializing the `adata->lock` mutex. This leads to a NULL dereference when the mutex is later acquired (e.g. in cros_typec_altmode_work()). Initialize the mutex in cros_typec_register_thunderbolt() to fix the issue.