drm/msm/dpu: fix error return code in dpu_encoder_init

Fix to return negative error code -ENOMEM with the use of
ERR_PTR from dpu_encoder_init.

Fixes: 25fdd59 ("drm/msm: Add SDM845 DPU support")
Signed-off-by: Chen Tao <chentao107@huawei.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -2187,7 +2187,7 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
 
 	dpu_enc = devm_kzalloc(dev->dev, sizeof(*dpu_enc), GFP_KERNEL);
 	if (!dpu_enc)
-		return ERR_PTR(ENOMEM);
+		return ERR_PTR(-ENOMEM);
 
 	rc = drm_encoder_init(dev, &dpu_enc->base, &dpu_encoder_funcs,
 			drm_enc_mode, NULL);