net: offload: fix device and driver names generated by DT device macros

Generated device and driver names have changed with commits [1] and [2],
but net offload drivers missed the conversion. Update net offload DT
device macros now.

[1] commit 8c1bef53 ("device: support generating defines from
  devicetree nodes with no label")
[2] commit f91e9fba ("device: fix potential truncation of DT-derived
  device names")

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>