hw/scsi/megasas: Fails command if SGL buffer overflows

hw/scsi/megasas: Fails command if SGL buffer overflows

If we detect an overflow on the SGL buffer, do not
keep processing the command: discard it. TARGET_FAILURE
sense code will be returned (MFI_STAT_SCSI_DONE_WITH_ERROR).

Reported-by: Alexander Bulekov <alxndr@bu.edu>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/521
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20211119201141.532377-2-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>