These drivers depend on the corresponding net drivers, or at least
common modules built under drivers/net/ethernet, currently leading
to duplicate modules.
I don't want to resolve this by adding a dependency between
nic-modules and scsi-modules, as that would pull in both into
installer images that previously only needed one set of drivers. I
also don't want to add the common modules into kernel-image as that
would bloat all installer images. Instead, put the drivers in a new
package and we can work out which installer images should include it
later.
Build scsi-nic-modules for all architectures/flavours that build
scsi-modules using the common module list now.