[Blackfin] arch: Give the DMA base registers a more descriptive name

The DMA base registers are available in a global named "base_addr" for
every Blackfin variant. Give this a more descriptive name, and remove
duplicate tables from some drivers.

Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/include/asm-blackfin/dma.h b/include/asm-blackfin/dma.h
index 16d4935..c0d5259 100644
--- a/include/asm-blackfin/dma.h
+++ b/include/asm-blackfin/dma.h
@@ -191,4 +191,7 @@
 void *dma_memcpy(void *dest, const void *src, size_t count);
 void *safe_dma_memcpy(void *dest, const void *src, size_t count);
 
+extern int channel2irq(unsigned int channel);
+extern struct dma_register *dma_io_base_addr[MAX_BLACKFIN_DMA_CHANNEL];
+
 #endif