megasas: Correct target/lun mapping
The structure to reference a logical drive has an unused field,
which can be used to carry the lun ID. This enabled seabios to
establish the proper target/LUN mapping.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>