Convert CONFIG_FEC_MXC to Kconfig

This converts the following to Kconfig:
	CONFIG_FEC_MXC

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/tqma6dl_mba6_spi_defconfig b/configs/tqma6dl_mba6_spi_defconfig
index b414597..839d6a0 100644
--- a/configs/tqma6dl_mba6_spi_defconfig
+++ b/configs/tqma6dl_mba6_spi_defconfig
@@ -48,6 +48,7 @@
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SPI_FLASH_WINBOND=y
 # CONFIG_SPI_FLASH_USE_4K_SECTORS is not set
+CONFIG_FEC_MXC=y
 CONFIG_MII=y
 CONFIG_PINCTRL=y
 CONFIG_PINCTRL_IMX6=y