[ARM] Convert DMA cache handling to take const void * args

The DMA cache handling functions take virtual addresses, but in the
form of unsigned long arguments.  This leads to a little confusion
about what exactly they take.  So, convert them to take const void *
instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/dma-mapping.h

@@ -17,7 +17,7 @@
  * platforms with CONFIG_DMABOUNCE.
  * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
  */
-extern void consistent_sync(void *kaddr, size_t size, int rw);
+extern void consistent_sync(const void *kaddr, size_t size, int rw);
 
 /*
  * Return whether the given device DMA address mask can be supported