CVE-2026-89859: scsi: qla2xxx: Zero dport diagnostics buffer to avoid info leak

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Zero dport diagnostics buffer to avoid info leak qla2x00_do_dport_diagnostics() allocates the qla_dport_diag response buffer with kmalloc_obj() (non-zeroing) and, on success, copies the full sizeof(*dd) back to user space via sg_copy_from_buffer(). The inbound sg_copy_to_buffer() only fills as many bytes as the user request payload provides, and qla26xx_dport_diagnostics() zeroes only dd->buf. The options and unused[] fields are therefore copied out uninitialized, leaking kernel heap contents to user space. Allocate with kzalloc_obj(), matching qla2x00_do_dport_diagnostics_v2().