While everything said about LACP is true, I'd like to give out a warning here in the case your customer expects a performance or throughput increase by this change.
Because wireless is half-duplex, and the data rates listed everywhere are gross data rates (with a lot of overhead), you are very unlikely to ever hit the 2 Gbit performance (full duplex) of a gigabit ethernet port. You are able to hit the gigabit mark only in a very controlled environment where all traffic from optimal clients, in an interference free environment, with data flowing in the same direction and on both radio's simultaneously.
So technically seen, it is unlikely that pulling 2 ethernet cables and occupying two switch port has a good return on investment. If you are really convinced that you need the bandwidth, the AP-335 with SmartRate 1, 2.5 or 5 Gbps over UTP might be a better investment.
What might be a good reason is to have redundant uplinks to your (separate) switches which can make the AP boot automatically from the other switch in case of a switch failure.