ARM: zynq: Enable USB1 as secondary boot device

Xilinx Zynq SoC has two usb controllers and both could be used as secondary
boot method.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

include/configs/zynq-common.h

@@ -117,7 +117,7 @@
 #endif
 
 #ifdef CONFIG_CMD_USB
-#define BOOT_TARGET_DEVICES_USB(func) func(USB, usb, 0)
+#define BOOT_TARGET_DEVICES_USB(func) func(USB, usb, 0) func(USB, usb, 1)
 #else
 #define BOOT_TARGET_DEVICES_USB(func)
 #endif