media: vidtv: Use kmemdup instead of kzalloc and memcpy

Fixes coccicheck warning:
drivers/media/test-drivers/vidtv/vidtv_psi.c:509:10-17: WARNING
opportunity for kmemdup
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/test-drivers/vidtv/vidtv_psi.c

@@ -506,10 +506,9 @@ struct vidtv_psi_desc *vidtv_psi_desc_clone(struct vidtv_psi_desc *desc)
 
 		case REGISTRATION_DESCRIPTOR:
 		default:
-			curr = kzalloc(sizeof(*desc) + desc->length, GFP_KERNEL);
+			curr = kmemdup(desc, sizeof(*desc) + desc->length, GFP_KERNEL);
 			if (!curr)
 				return NULL;
-			memcpy(curr, desc, sizeof(*desc) + desc->length);
 		}
 
 		if (!curr)