pdc202xx_old: ignore "FIFO empty" bit in test_irq() method

The driver takes into account not only the interrupt status bit but
also "FIFO empty" bit in its test_irq() method. This actually is a
superfluous check since for the DMA commands calling the
dma_test_irq() method further in the interrupt handler makes sure FIFO
is emptied.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>