drivers: ptp_clock_nxp_enet: misc fixes

1. Correct node label in k64 overlay for ptp test
   - Not sure if this actually matters since it appears
     that actual hardware is no longer tested in net tests

2. Include fsl_enet with <> instead of "".

3. Build the ptp clock driver only if the ethernet driver is built
   - Technically I think the 1588 timer should be able to be used
     even if the ethernet mac is not used, but I would imagine this
     to be an extraordinarily rare, weird, and niche use case, so to fix
     the current CI error caused by net test disabling ethernet drivers,
     couple the ptp clock driver to the ethernet driver in the build
     configuration.

Signed-off-by: Declan Snyder <declan.snyder@nxp.com>
3 files changed