ide: don't set hwif->dma_ops in init_dma() method

Replace setting of 'hwif->dma_ops' in the 'alim15x3' and 'palm_bk3710' drivers'
init_dma() methods with initializing the corresponding member of their 'struct
ide_port_info' instances and remove such setting from the 'hpt366' driver that
just doesn't use 'sff_dma_ops'. Along with some code save, this prepares us for
the next patch...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>