m68k: Sort out !CONFIG_MMU_SUN3 vs. CONFIG_HAS_DMA

In two places, we check !CONFIG_MMU_SUN3 while we should check
CONFIG_HAS_DMA instead.
While fixing this, the check in <asm/dma-mapping.h> became redundant
(<linux/dma-mapping.h> already handles this case), so just remove it.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/include/asm/dma-mapping.h

@@ -5,7 +5,6 @@
 
 struct scatterlist;
 
-#ifndef CONFIG_MMU_SUN3
 static inline int dma_supported(struct device *dev, u64 mask)
 {
 	return 1;
@@ -111,10 +110,6 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t handle)
 	return 0;
 }
 
-#else
-#include <asm-generic/dma-mapping-broken.h>
-#endif
-
 /* drivers/base/dma-mapping.c */
 extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 			   void *cpu_addr, dma_addr_t dma_addr, size_t size);