m68k: dma: Remove unnecessary include of asm/cacheflush.h

In commit ca15ca40 ("mm: remove unneeded includes of
<asm/pgalloc.h>"), asm/cacheflush.h independent on the MACRO
was included at line 18. The include here is unnecessary. Remove it.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20210510030836.11834-1-wanjiabing@vivo.comSigned-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/kernel/dma.c

@@ -34,9 +34,6 @@ pgprot_t pgprot_dmacoherent(pgprot_t prot)
 	return prot;
 }
 #else
-
-#include <asm/cacheflush.h>
-
 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t gfp, unsigned long attrs)
 {