configs: Migrate CONFIG_USB_STORAGE

In some cases we were missing CONFIG_USB=y so enable that when needed.

Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/sama5d3xek_spiflash_defconfig b/configs/sama5d3xek_spiflash_defconfig
index a938fe7..064b9a9 100644
--- a/configs/sama5d3xek_spiflash_defconfig
+++ b/configs/sama5d3xek_spiflash_defconfig
@@ -20,6 +20,7 @@
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_ATMEL=y
 CONFIG_USB=y
+CONFIG_USB_STORAGE=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_ATMEL_USBA=y
 CONFIG_OF_LIBFDT=y