pdc202xx_old: use ide_dma_test_irq()

The driver's dma_test_irq() method, although tests some chip specific interrupt
bits, finally always relies on the SFF-8038i standard interrupt bit.  I see no
point in testing the bits that are not trusted anyway -- the driver should be
fully able to use the standard method implemetation, ide_dma_test_irq().

With this change 'pdc202xx_dma_ops' finally becomes identical to 'sff_dma_ops',
and we can get rid of it...

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