udev: Handle PTP device symlink properly on udev action 'change'

PTP device symlink creation rules are currently executed only when the
udev action is 'add'. If a user reloads the rules and runs the udevadm
trigger command to reapply changes, the symlink may be deleted, which
can prevent the chronyd service from restarting properly.

Signed-off-by: Chengen Du <chengen.du@canonical.com>
(cherry picked from commit 6bd12be)

Resolves: RHEL-59871

rules.d/50-udev-default.rules.in

@@ -30,6 +30,9 @@ SUBSYSTEM=="pci|usb|platform", IMPORT{builtin}="path_id"
 
 SUBSYSTEM=="net", IMPORT{builtin}="net_driver"
 
+SUBSYSTEM=="ptp", ATTR{clock_name}=="KVM virtual PTP", SYMLINK+="ptp_kvm"
+SUBSYSTEM=="ptp", ATTR{clock_name}=="hyperv", SYMLINK+="ptp_hyperv"
+
 ACTION!="add", GOTO="default_end"
 
 SUBSYSTEM=="tty", KERNEL=="ptmx", GROUP="tty", MODE="0666"
@@ -116,7 +119,4 @@ KERNEL=="vhost-net", GROUP="kvm", MODE="{{DEV_KVM_MODE}}", OPTIONS+="static_node
 
 KERNEL=="udmabuf", GROUP="kvm"
 
-SUBSYSTEM=="ptp", ATTR{clock_name}=="KVM virtual PTP", SYMLINK+="ptp_kvm"
-SUBSYSTEM=="ptp", ATTR{clock_name}=="hyperv", SYMLINK+="ptp_hyperv"
-
 LABEL="default_end"