dmaengine: mmp_pdma: Add clock support

Add support for retrieving and enabling an optional clock during
mmp_pdma_probe(). It is optional because in Marvell devices
such as "marvell,pdma-1.0" the clocks property is not a required
property. But in SpacemiT K1 PDMA, "spacemit,k1-pdma" as the dt
binding schema file stated, clocks is required.

Signed-off-by: Guodong Xu <guodong@riscstar.com>
Link: https://lore.kernel.org/r/20250822-working_dma_0701_v2-v5-2-f5c0eda734cc@riscstar.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: docularxu

drivers/dma/mmp_pdma.c

@@ -15,6 +15,7 @@
 #include <linux/device.h>
 #include <linux/platform_data/mmp_dma.h>
 #include <linux/dmapool.h>
+#include <linux/clk.h>
 #include <linux/of_dma.h>
 #include <linux/of.h>
 
@@ -1019,6 +1020,7 @@ static int mmp_pdma_probe(struct platform_device *op)
 {
 	struct mmp_pdma_device *pdev;
 	struct mmp_dma_platdata *pdata = dev_get_platdata(&op->dev);
+	struct clk *clk;
 	int i, ret, irq = 0;
 	int dma_channels = 0, irq_num = 0;
 	const enum dma_slave_buswidth widths =
@@ -1037,6 +1039,10 @@ static int mmp_pdma_probe(struct platform_device *op)
 	if (IS_ERR(pdev->base))
 		return PTR_ERR(pdev->base);
 
+	clk = devm_clk_get_optional_enabled(pdev->dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
 	if (pdev->dev->of_node) {
 		/* Parse new and deprecated dma-channels properties */
 		if (of_property_read_u32(pdev->dev->of_node, "dma-channels",