This is a read-only attribute that shows which LPs are currently
configured to run on this card (it is the opposite side of the LP
component's mainCard and spareCard link attributes). Note that
there is only one case where more than one LP can be configured to
run on a card. This is when the card is configured as an N+1 spare.
If this is not the case, the card is configured as a main card or as a
1for1 spare, only one LP can appear in this list.