usb: zynq: Define config USB_STORAGE through defconfig

Define config USB_STORAGE through defconfig for all
respective zynq boards

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/zynq_zc706_defconfig b/configs/zynq_zc706_defconfig
index c13c077..a03f96e 100644
--- a/configs/zynq_zc706_defconfig
+++ b/configs/zynq_zc706_defconfig
@@ -43,6 +43,7 @@
 CONFIG_USB_ULPI_VIEWPORT=y
 CONFIG_USB_ULPI=y
 CONFIG_USB_GADGET=y
+CONFIG_USB_STORAGE=y
 CONFIG_CI_UDC=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_G_DNL_MANUFACTURER="Xilinx"