Fixes in translation in PCI to DMA address to fix boot problems with

Fixes in translation in PCI to DMA address to fix boot problems with
Linux 2.6 with DMA support

dev/ide_disk.cc:
    Add debug infomation for DMA transfers and fix handling of PRD pointer
    values
dev/ide_disk.hh:
    Reduce buffer (MAX_DMA) size to 64K
dev/tsunami_pchip.cc:
dev/tsunami_pchip.hh:
    Add handling of PCTL register and also fix the translate from PCI to DMA
    addresses which was incorrect

--HG--
extra : convert_revision : 562f55fa1c7099ad0f5a23f59dec2c8ec7601d43