can: etas_es58x: allow partial RX URB allocation to succeed

In the Linux kernel, the following vulnerability has been resolved: can: etas_es58x: allow partial RX URB allocation to succeed When es58x_alloc_rx_urbs() fails to allocate the requested number of URBs but succeeds in allocating some, it returns an error code. This causes es58x_open() to return early, skipping the cleanup label 'free_urbs', which leads to the anchored URBs being leaked. As pointed out by maintainer Vincent Mailhol, the driver is designed to handle partial URB allocation gracefully. Therefore, partial allocation should not be treated as a fatal error. Modify es58x_alloc_rx_urbs() to return 0 if at least one URB has been allocated, restoring the intended behavior and preventing the leak in es58x_open().