Revert "interfaces: use same approach as ppp-linkup script #5367"
Revert "interfaces: use same approach as ppp-linkup script #5367"

This reverts commit a8522b7243e6b0fe76c91ccf52a9128d5fa9d0f6.

opnsense/core,opnsense/core,opnsense/core,opnsense/core,opnsense/core,opnsense/core