usb: lvstest: Fix sparse warnings generated by kbuild test bot

Following sparse warnings were reported by kbuild test bot

drivers/usb/misc/lvstest.c:314:28: sparse: incorrect type in assignment (different base types)
   drivers/usb/misc/lvstest.c:314:28:    expected unsigned short [unsigned] [usertype] portchange
   drivers/usb/misc/lvstest.c:314:28:    got restricted __le16 [usertype] wPortChange
drivers/usb/misc/lvstest.c:332:40: sparse: restricted __le16 degrades to integer

This patch fixes above warnings.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>