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/P1020MBG-PC_36BIT_defconfig b/configs/P1020MBG-PC_36BIT_defconfig
index 0641209..470dfa0 100644
--- a/configs/P1020MBG-PC_36BIT_defconfig
+++ b/configs/P1020MBG-PC_36BIT_defconfig
@@ -26,10 +26,10 @@
 CONFIG_CMD_FAT=y
 CONFIG_ENV_IS_IN_FLASH=y
 CONFIG_MTD_NOR_FLASH=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