Remove dma_cache_(wback|inv|wback_inv) functions

Remove dma_cache_(wback|inv|wback_inv) functions

dma_cache_(wback|inv|wback_inv) were the earliest attempt on a generalized
cache managment API for I/O purposes.  Originally it was basically the raw
MIPS low level cache API exported to the entire world.  The API has
suffered from a lack of documentation, was not very widely used unlike it's
more modern brothers and can easily be replaced by dma_cache_sync.  So
remove it rsp.  turn the surviving bits back into an arch private API, as
discussed on linux-arch.

Signed-off-by: Ralf Baechle <[email protected]>
Acked-by: Paul Mundt <[email protected]>
Acked-by: Paul Mackerras <[email protected]>
Acked-by: David S. Miller <[email protected]>
Acked-by: Kyle McMartin <[email protected]>
Acked-by: Haavard Skinnemoen <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>