treewide: Migrate CONFIG_TSEC_ENET to Kconfig

Migrate the CONFIG_TSEC_ENET option to Kconfig.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/configs/P2020RDB-PC_defconfig b/configs/P2020RDB-PC_defconfig
index 8022a5e..9654a13 100644
--- a/configs/P2020RDB-PC_defconfig
+++ b/configs/P2020RDB-PC_defconfig
@@ -31,10 +31,10 @@
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SPANSION=y
-CONFIG_PHYLIB=y
 CONFIG_NETDEVICES=y
 CONFIG_PHY_GIGE=y
 CONFIG_E1000=y
+CONFIG_TSEC_ENET=y
 CONFIG_SYS_NS16550=y
 CONFIG_FSL_ESPI=y
 CONFIG_USB=y