net: usb: lan78xx: Fix double free issue with interrupt buffer allocation

In the Linux kernel, the following vulnerability has been resolved: net: usb: lan78xx: Fix double free issue with interrupt buffer allocation In lan78xx_probe(), the buffer `buf` was being freed twice: once implicitly through `usb_free_urb(dev->urb_intr)` with the `URB_FREE_BUFFER` flag and again explicitly by `kfree(buf)`. This caused a double free issue. To resolve this, reordered `kmalloc()` and `usb_alloc_urb()` calls to simplify the initialization sequence and removed the redundant `kfree(buf)`. Now, `buf` is allocated after `usb_alloc_urb()`, ensuring it is correctly managed by `usb_fill_int_urb()` and freed by `usb_free_urb()` as intended.