scsi: qla2xxx: Zero mailbox struct in qla2x00_get_firmware_state()

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Zero mailbox struct in qla2x00_get_firmware_state() The mbx_cmd_t is allocated on the stack but left uninitialized. qla2x00_mailbox_command() has several early-return paths (PCI permanent failure, device failed, EEH busy, ISP abort pending, mailbox access timeout, purge mbox) that return without writing the input mailbox registers back into mcp->mb[]. qla2x00_get_firmware_state() then unconditionally copies mcp->mb[1..6] (and mb[12]) into the caller's states[] array regardless of the return value. On such a failure the copied values are uninitialized kernel stack memory, which is then exposed to userspace via the fw_state and mpi_fw_state sysfs handlers. Zero the mailbox struct so a failed query yields deterministic zeroed state instead of leaking stack contents.