usb: gadget: make composite module options readonly only

This is a partly revert of 4fffd6e5 ("usb: gadget: composite: make
module parameters accessible at runtime").
It is not possible to change the VID or other property for a gadget
right now. This change has been made for Anrdoid gadget which has this
functionality in its copy of the file. This function is executed currently
only once and most caller in tree are __init.
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/composite.c

@@ -34,27 +34,27 @@
  */
 
 static ushort idVendor;
-module_param(idVendor, ushort, 0644);
+module_param(idVendor, ushort, S_IRUGO);
 MODULE_PARM_DESC(idVendor, "USB Vendor ID");
 
 static ushort idProduct;
-module_param(idProduct, ushort, 0644);
+module_param(idProduct, ushort, S_IRUGO);
 MODULE_PARM_DESC(idProduct, "USB Product ID");
 
 static ushort bcdDevice;
-module_param(bcdDevice, ushort, 0644);
+module_param(bcdDevice, ushort, S_IRUGO);
 MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");
 
 static char *iManufacturer;
-module_param(iManufacturer, charp, 0644);
+module_param(iManufacturer, charp, S_IRUGO);
 MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");
 
 static char *iProduct;
-module_param(iProduct, charp, 0644);
+module_param(iProduct, charp, S_IRUGO);
 MODULE_PARM_DESC(iProduct, "USB Product string");
 
 static char *iSerialNumber;
-module_param(iSerialNumber, charp, 0644);
+module_param(iSerialNumber, charp, S_IRUGO);
 MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");
 
 static char composite_manufacturer[50];
@@ -1478,16 +1478,12 @@ static int composite_bind(struct usb_gadget *gadget,
 	/* standardized runtime overrides for device ID data */
 	if (idVendor)
 		cdev->desc.idVendor = cpu_to_le16(idVendor);
-	else
-		idVendor = le16_to_cpu(cdev->desc.idVendor);
+
 	if (idProduct)
 		cdev->desc.idProduct = cpu_to_le16(idProduct);
-	else
-		idProduct = le16_to_cpu(cdev->desc.idProduct);
+
 	if (bcdDevice)
 		cdev->desc.bcdDevice = cpu_to_le16(bcdDevice);
-	else
-		bcdDevice = le16_to_cpu(cdev->desc.bcdDevice);
 
 	/* string overrides */
 	if (iManufacturer || !cdev->desc.iManufacturer) {