usbtest: make module param pattern writeable

Allow module_param to be writeable. This allows us to change
the parameter if usbtest is built-in in the kernel.
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/usbtest.c

@@ -213,8 +213,9 @@ static struct urb *simple_alloc_urb (
 }
 
 static unsigned pattern = 0;
-module_param (pattern, uint, S_IRUGO);
-MODULE_PARM_DESC(pattern, "i/o pattern (0 == zeroes)");
+static unsigned mod_pattern;
+module_param_named(pattern, mod_pattern, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(mod_pattern, "i/o pattern (0 == zeroes)");
 
 static inline void simple_fill_buf (struct urb *urb)
 {
@@ -1567,6 +1568,8 @@ usbtest_ioctl (struct usb_interface *intf, unsigned int code, void *buf)
 
 	// FIXME USBDEVFS_CONNECTINFO doesn't say how fast the device is.
 
+	pattern = mod_pattern;
+
 	if (code != USBTEST_REQUEST)
 		return -EOPNOTSUPP;