ieee1394: move init_ohci1394_dma to drivers/firewire/

because drivers/ieee1394/ will be deleted.

Additional changes:
  - add some #include directives
  - adjust to use firewire/ohci.h instead of ieee1394/ohci1394.h,
    replace struct ti_ohci by a minimal struct ohci,
    replace quadlet_t from ieee1394_types.h by u32
  - two or three trivial stylistic changes
  - __iomem annotation

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>