usb: gadget: uvc: fix permissions of configfs attributes

76e0da34 "usb-gadget/uvc: use per-attribute show and store methods"
removed write permission for writeable attributes. Correct attribute
permissions.

Fixes: 76e0da34 "usb-gadget/uvc: use per-attribute show and store methods"
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/uvc_configfs.c

@@ -20,7 +20,7 @@
 #define UVC_ATTR(prefix, cname, aname) \
 static struct configfs_attribute prefix##attr_##cname = { \
 	.ca_name	= __stringify(aname),				\
-	.ca_mode	= S_IRUGO,					\
+	.ca_mode	= S_IRUGO | S_IWUGO,				\
 	.ca_owner	= THIS_MODULE,					\
 	.show		= prefix##cname##_show,				\
 	.store		= prefix##cname##_store,			\