net: ks8851: Add Kconfig entries

Convert CONFIG_KS8851_MLL and CONFIG_KS8851_MLL_BASEADDR to Kconfig

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Eugen Hristev <eugen.hristev@microchip.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/at91sam9n12ek_nandflash_defconfig b/configs/at91sam9n12ek_nandflash_defconfig
index b02be84..fd6d13d 100644
--- a/configs/at91sam9n12ek_nandflash_defconfig
+++ b/configs/at91sam9n12ek_nandflash_defconfig
@@ -48,6 +48,8 @@
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SF_DEFAULT_SPEED=30000000
 CONFIG_SPI_FLASH_ATMEL=y
+CONFIG_KS8851_MLL=y
+CONFIG_KS8851_MLL_BASEADDR=0x30000000
 CONFIG_PINCTRL=y
 CONFIG_PINCTRL_AT91=y
 CONFIG_DM_SERIAL=y