usbip: Fix sscanf handling

Scan only to the length permitted by the buffer

One of a set of sscanf problems noted by Jackie Chang

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/staging/usbip/userspace/libsrc/usbip_common.c
Simple merge

diff --cc drivers/staging/usbip/userspace/libsrc/vhci_driver.c
Simple merge