dpll: export __dpll_device_change_ntf() for use under dpll_lock

dpll: export __dpll_device_change_ntf() for use under dpll_lock

Export __dpll_device_change_ntf() so that drivers can send device
change notifications from within device callbacks, which are already
called under dpll_lock. Using dpll_device_change_ntf() in that
context would deadlock.

Add lockdep_assert_held() to catch misuse without the lock held.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/20260526074525.1451008-2-ivecera@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>