Fix shift out-of-bounds in vhci_hcd.c:

  UBSAN: shift-out-of-bounds in ../drivers/usb/usbip/vhci_hcd.c:399:41
  shift exponent 768 is too large for 32-bit type 'int'

Fixes: 03cd00d5 ("usbip: vhci-hcd: Set the vhci structure up to work")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: syzbot+297d20e437b79283bf6d@syzkaller.appspotmail.com
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201229071309.18418-1-rdunlap@infradead.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>