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/BSC9131RDB_SPIFLASH_SYSCLK100_defconfig b/configs/BSC9131RDB_SPIFLASH_SYSCLK100_defconfig
index b1b0ac7..7696681 100644
--- a/configs/BSC9131RDB_SPIFLASH_SYSCLK100_defconfig
+++ b/configs/BSC9131RDB_SPIFLASH_SYSCLK100_defconfig
@@ -27,7 +27,8 @@
 # CONFIG_MMC is not set
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SPANSION=y
-CONFIG_PHYLIB=y
+CONFIG_NETDEVICES=y
+CONFIG_TSEC_ENET=y
 # CONFIG_PCI is not set
 CONFIG_SYS_NS16550=y
 CONFIG_FSL_ESPI=y