USB: core: Change usb_get_device_descriptor() API

USB: core: Change usb_get_device_descriptor() API

The usb_get_device_descriptor() routine reads the device descriptor
from the udev device and stores it directly in udev->descriptor.  This
interface is error prone, because the USB subsystem expects in-memory
copies of a device's descriptors to be immutable once the device has
been initialized.

The interface is changed so that the device descriptor is left in a
kmalloc-ed buffer, not copied into the usb_device structure.  A
pointer to the buffer is returned to the caller, who is then
responsible for kfree-ing it.  The corresponding changes needed in the
various callers are fairly small.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>