drm/komeda: Add support for 'memory-region' DT node property

The 'memory-region' property of the komeda display driver DT binding
allows the use of a 'reserved-memory' node for buffer allocations. Add
the requisite of_reserved_mem_device_{init,release} calls to actually
make use of the memory if present.

Changes since v1:
- Move handling inside komeda_parse_dt

Signed-off-by: Mihail Atanassov <[e-mail]>
Signed-off-by: Ayan Kumar Halder <[e-mail]>
Reviewed-by: James Qian Wang (Arm Technology China) <[e-mail]>
Link:- https://patchwork.kernel.org/patch/11076413/

drivers/gpu/drm/arm/display/komeda/komeda_dev.c

···
 #include <linux/iommu.h>
 #include <linux/of_device.h>
 #include <linux/of_graph.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #ifdef CONFIG_DEBUG_FS
···
 		DRM_ERROR("could not get IRQ number.\n");
 		return mdev->irq;
 	}
+
+	/* Get the optional framebuffer memory resource */
+	ret = of_reserved_mem_device_init(dev);
+	if (ret && ret != -ENODEV)
+		return ret;
+	ret = 0;
 
 	for_each_available_child_of_node(np, child) {
 		if (of_node_cmp(child->name, "pipeline") == 0) {
···
 	}
 
 	mdev->n_pipelines = 0;
+
+	of_reserved_mem_device_release(dev);
 
 	if (funcs && funcs->cleanup)
 		funcs->cleanup(mdev);