Problem mapping multiple definitions of a structure coming from different modules

[Ryan Stone]

I don't have a system with separate em or igb modules so I can't test this,
but I was under the impression that you could make this work with a syntax
along the lines of:

struct if_em`tx_ring

or

struct if_em.ko`tx_ring


Unfortunately, this doesn't help those who have the drivers compiler into
their kernel, but it should work for you.