ARM: realview: enable USB storage in the defconfig

It is not uncommon to boot a root filesystem from a USB
pendrive and similar, so enable USB mass storage, backed
by SCSI and SD block devices in the RealView defconfig.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/configs/realview_defconfig

@@ -48,6 +48,8 @@ CONFIG_MTD_CFI_AMDSTD=y
 CONFIG_MTD_ROM=y
 CONFIG_MTD_PHYSMAP=y
 CONFIG_ARM_CHARLCD=y
+CONFIG_SCSI=y
+CONFIG_BLK_DEV_SD=y
 CONFIG_NETDEVICES=y
 CONFIG_SMC91X=y
 CONFIG_SMSC911X=y
@@ -76,6 +78,7 @@ CONFIG_SND_PCM_OSS=y
 # CONFIG_SND_DRIVERS is not set
 CONFIG_SND_ARMAACI=y
 CONFIG_USB=y
+CONFIG_USB_STORAGE=y
 CONFIG_USB_ISP1760=y
 CONFIG_MMC=y
 CONFIG_MMC_ARMMMCI=y