drm/amdgpu: add missed return value set for error case

Return value should be set when going to error handle tag
for error case, this can avoid potential invalid array
access by upper caller.
Signed-off-by: NGuchun Chen <guchun.chen@amd.com>
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c

@@ -1311,6 +1311,7 @@ static int amdgpu_ras_badpages_read(struct amdgpu_device *adev,
 	data = con->eh_data;
 	if (!data || data->count == 0) {
 		*bps = NULL;
+		ret = -EINVAL;
 		goto out;
 	}