USB: fix trivial usb_device kernel-doc errors

Fix trivial kernel-doc warnings:
Warning(include/linux/usb.h:574): No description found for parameter 'usb3_lpm_enabled'
Warning(include/linux/usb.h:574): Excess struct/union/enum/typedef member 'usb_classdev' description in 'usb_device'
Warning(include/linux/usb.h:574): Excess struct/union/enum/typedef member 'usbfs_dentry' description in 'usb_device'

Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/usb.h

@@ -469,14 +469,12 @@ struct usb3_lpm_parameters {
  * @lpm_capable: device supports LPM
  * @usb2_hw_lpm_capable: device can perform USB2 hardware LPM
  * @usb2_hw_lpm_enabled: USB2 hardware LPM enabled
+ * @usb3_lpm_enabled: USB3 hardware LPM enabled
  * @string_langid: language ID for strings
  * @product: iProduct string, if present (static)
  * @manufacturer: iManufacturer string, if present (static)
  * @serial: iSerialNumber string, if present (static)
  * @filelist: usbfs files that are open to this device
- * @usb_classdev: USB class device that was created for usbfs device
- *	access from userspace
- * @usbfs_dentry: usbfs dentry entry for the device
  * @maxchild: number of ports if hub
  * @quirks: quirks of the whole device
  * @urbnum: number of URBs submitted for the whole device