net: ethernet: ti: am65-cpsw: Fix NAPI registration sequence

In the Linux kernel, the following vulnerability has been resolved:

net: ethernet: ti: am65-cpsw: Fix NAPI registration sequence

Registering the interrupts for TX or RX DMA Channels prior to registering

their respective NAPI callbacks can result in a NULL pointer dereference.

This is seen in practice as a random occurrence since it depends on the

randomness associated with the generation of traffic by Linux and the

reception of traffic from the wire.