ice: check netlist before enabling ICE_F_GNSS

Similar to the change made for ICE_F_SMA_CTRL, check the netlist before
enabling support for ICE_F_GNSS. This ensures that the driver only enables
the GNSS feature on devices which actually have the feature enabled in the
firmware device configuration.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Sunitha Mekala <sunithax.d.mekala@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>