dev_node_t was only used to transport some minor/major numbers
from the PCMCIA device drivers to deprecated userspace helpers.
However, only a few drivers made use of it, and the userspace
helpers are deprecated anyways. Therefore, get rid of dev_node_t .
As a first step, remove any usage of dev_node_t from drivers which
only wrote to this typedef/struct, but did not make use of it.