arm: shannon_defconfig: disable IDE subsystem

This patch disables deprecated IDE subsystem in shannon_defconfig
(no IDE host drivers are selected in this config so there is no
valid reason to enable IDE subsystem itself).

Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

arch/arm/configs/shannon_defconfig

@@ -25,7 +25,6 @@ CONFIG_MTD_CFI_AMDSTD=y
 CONFIG_MTD_SA1100=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_SIZE=8192
-CONFIG_IDE=m
 CONFIG_NETDEVICES=y
 CONFIG_NET_ETHERNET=y
 CONFIG_NET_PCMCIA=y