[ALSA] au88x0: Remove unneeded call to pci_dma_supported()
Modules: au88x0 driver
pci_dma_supported() is called right before pci_set_dma_mask() which already
calls pci_dma_supported(). The attached patch removes the unneeded call to
pci_dma_supported()
Additionally the custom VORTEX_DMA_MASK macro is replaced by DMA_32BIT_MASK
from linux/dma-mapping.h