Yes, the Samsung S6 wireless charger can be used to charge the Huawei P40 Pro, as they both support the wireless charging standard Qi. However, since the Huawei P40 Pro supports faster wireless charging power (up to 27W), if you want faster charging speeds, you may need to use Huawei's officially recommended wireless charger.
Any wireless charging base can charge Huawei mobile phones. However, to improve the charging quality, you are advised to purchase Huawei brand charging base Samsung in Huawei Mall