aec62xx: rework init_setup_aec6x80()

Rework init_setup_aec6x80() so that it won't rewrite the constant name strings
anymore -- in order to do this:

- in aec62xx_init_one(), pass a local copy of 'struct pci_device_id' down the
  call chain;

- change the names for in aec62xx_chipsets[] to default to AEC-6280[R];

- override the 'name' field in init_setup_aec6x80() only if bit 4 of the DMA
  status register is set.

While at it, also change the 'udma_mask' field for AEC-6x80R chips in this
function and remove the code doing the same from the init_hwif() method...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>