Several changes to make it compile under the new abstraction

- probe and remove are related to an fmc_driver structure. Thus
the fd-spec.c is obsolete.  Still, the driver is bound to the spec
and as such it refuses to initialize under a different carrier.

- we don't have "spec" in the structure but "fmc"

- i2c referred to pdev, but has been cleaned up

- fd-zio unfortunately refers to pdev to build the local ID.

Still a lot of details are to be fixed.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>