kernel/dma: remove unnecessary unmap_kernel_range

vunmap will remove ptes.

Link: https://lkml.kernel.org/r/20210322021806.892164-3-npiggin@gmail.comSigned-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Cédric Le Goater <clg@kaod.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/dma/remap.c

@@ -66,6 +66,5 @@ void dma_common_free_remap(void *cpu_addr, size_t size)
 		return;
 	}
 
-	unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
 	vunmap(cpu_addr);
 }