drm/amdgpu: Use kmalloc_array() in amdgpu_debugfs_gca_config_read()

A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "kmalloc_array".

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -2712,7 +2712,7 @@ static ssize_t amdgpu_debugfs_gca_config_read(struct file *f, char __user *buf,
 	if (size & 0x3 || *pos & 0x3)
 		return -EINVAL;
 
-	config = kmalloc(256 * sizeof(*config), GFP_KERNEL);
+	config = kmalloc_array(256, sizeof(*config), GFP_KERNEL);
 	if (!config)
 		return -ENOMEM;