boards: arm: frdm_k64f: don't use ETH if MODEM is enabled

Let's change the specific WNC-M14A2A check into a more generic
MODEM check for enabling ethernet.  Many of these pins are used
on the Arduino headers.

Signed-off-by: Michael Scott <[email protected]>

Author: mike-scott

boards/arm/frdm_k64f/Kconfig.defconfig

@@ -101,7 +101,7 @@ endif # SPI
 if NETWORKING
 
 config NET_L2_ETHERNET
-	default y if !MODEM_WNCM14A2A
+	default y if !MODEM
 
 config ETH_MCUX_0
 	default y if NET_L2_ETHERNET