parisc: Remove 32-bit DMA enforcement from sba_iommu

This breaks booting from sata_sil24 with the recent DMA change.
According to James Bottomley this was in to improve performance by
kicking the device into 32 bit descriptors, which are usually more
efficient, especially with older dual descriptor format cards like we
have on parisc systems.
Remove it for now to make DMA working again.

Fixes: dcc02c19 ("sata_sil24: use dma_set_mask_and_coherent")
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>