drm: xlnx: zynqmp: fix a memset in zynqmp_dp_train()

The dp->train_set[] for this driver is only two characters, not four so
this memsets too much.  Fortunately, this ends up corrupting a struct
hole and not anything important.

Fixes: d76271d2 ("drm: xlnx: DRM/KMS driver for Xilinx ZynqMP DisplayPort Subsystem")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/YGLwCBMotnrKZu6P@mwanda

drivers/gpu/drm/xlnx/zynqmp_dp.c

@@ -866,7 +866,7 @@ static int zynqmp_dp_train(struct zynqmp_dp *dp)
 		return ret;
 
 	zynqmp_dp_write(dp, ZYNQMP_DP_SCRAMBLING_DISABLE, 1);
-	memset(dp->train_set, 0, 4);
+	memset(dp->train_set, 0, sizeof(dp->train_set));
 	ret = zynqmp_dp_link_train_cr(dp);
 	if (ret)
 		return ret;