This is a major change, work of Michel Arruat, then re-committed as a
single commit by Alessandro.  The original development happened mainly
on the SVEC carrier, and support for SPEC (PCI) was added back at a
later time.  I (Alessandro) chose to pick individual changes one at
a time, for better documentation and later "git blame", up to this point.

Now, this is a big commit that completely changes the driver,
mainly in the following places:

  - split carrier-specific from generic code, like the TDC driver is now
    (this is mainly the dma-specific and irq-specific code)
  - use of SDB to get base addresses (with new fmc-util file)
  - use the VIC core to manage interrupts, relying on carrier support
  - change the field-desc table for the better
  - add carrier-specific init, reset, exit
  - split irq and adc-specific stuff out of zio-drv.c
  - DMA data and interrupt is now different: the timestamp is at end-of-data,
    thus we don't have the "trigger-happened" interrupt any more
  - use a work queue for interrupt management, instead of a tasklet, this
    allows sleeping, which is needed by this code base
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>