[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

Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>