microblaze: Dont enable UBI support by default

This patch removes UBI support from defconfig and it can
be enabled from menuconfig as per need.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

configs/microblaze-generic_defconfig

@@ -35,10 +35,6 @@ CONFIG_CMD_TFTPPUT=y
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_JFFS2=y
-CONFIG_MTDIDS_DEFAULT="nor0=flash-0"
-CONFIG_MTDPARTS_DEFAULT="mtdparts=flash-0:256k(u-boot),256k(env),3m(kernel),1m(romfs),1m(cramfs),-(jffs2)"
-CONFIG_CMD_UBI=y
-# CONFIG_CMD_UBIFS is not set
 CONFIG_SPL_OF_CONTROL=y
 CONFIG_OF_EMBED=y
 CONFIG_NETCONSOLE=y