Revert "[baseimage] Delay ntp-config service to start after 5 minutes (sonic-net#2494)" (sonic-net#2590)

This reverts commit 33fe8d2.

Author: yxieca

files/build_templates/ntp-config.timer

@@ -302,9 +302,7 @@ sudo LANG=C cp $SCRIPTS_DIR/syncd.sh $FILESYSTEM_ROOT/usr/local/bin/syncd.sh
 # Copy systemd timer configuration
 # It implements delayed start of services
 sudo cp $BUILD_TEMPLATES/snmp.timer $FILESYSTEM_ROOT/etc/systemd/system/
-sudo cp $BUILD_TEMPLATES/ntp-config.timer $FILESYSTEM_ROOT/etc/systemd/system/
 sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable snmp.timer
-sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable ntp-config.timer
 
 sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get remove -y python-dev
 sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get clean -y