video: fbdev-MMP: Remove call to memset after dma_alloc_coherent

In commit 518a2f19
("dma-mapping: zero memory returned from dma_alloc_*"),
dma_alloc_coherent has already zeroed the memory.
So memset is not needed.
Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190715032017.7311-1-huangfq.daxian@gmail.com

drivers/video/fbdev/mmp/fb/mmpfb.c

@@ -612,7 +612,6 @@ static int mmpfb_probe(struct platform_device *pdev)
 		ret = -ENOMEM;
 		goto failed_destroy_mutex;
 	}
-	memset(fbi->fb_start, 0, fbi->fb_size);
 	dev_info(fbi->dev, "fb %dk allocated\n", fbi->fb_size/1024);
 
 	/* fb power on */