Merge existing fixes from spi/for-5.15

drivers/spi/spi-rockchip.c

···
 	int ret;
 	bool use_dma;
 
+	/* Zero length transfers won't trigger an interrupt on completion */
+	if (!xfer->len) {
+		spi_finalize_current_transfer(ctlr);
+		return 1;
+	}
+
 	WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) &&
 		(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY));
 

drivers/spi/spi-tegra20-slink.c

···
 	struct dma_async_tx_descriptor		*tx_dma_desc;
 };
 
-static int tegra_slink_runtime_suspend(struct device *dev);
-static int tegra_slink_runtime_resume(struct device *dev);
-
 static inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
 		unsigned long reg)
 {
···
 }
 #endif
 
+#ifdef CONFIG_PM
 static int tegra_slink_runtime_suspend(struct device *dev)
 {
 	struct spi_master *master = dev_get_drvdata(dev);
···
 	}
 	return 0;
 }
+#endif /* CONFIG_PM */
 
 static const struct dev_pm_ops slink_pm_ops = {
 	SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,