[ARM] Rename ISA mach/dma.h header to mach/isa-dma.h

This avoids confusion with platform specific DMA implementations in
mach/dma.h

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h
index 0641998..df5638f 100644
--- a/arch/arm/include/asm/dma.h
+++ b/arch/arm/include/asm/dma.h
@@ -21,7 +21,7 @@
 
 typedef unsigned int dmach_t;
 
-#include <mach/dma.h>
+#include <mach/isa-dma.h>
 
 /*
  * DMA modes