ipc3: fix subsize check

The ext size is counted as part of the ipc header size. The process size
and header size need to be less than the ipc max size.

Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>

src/ipc/ipc3/helper.c

@@ -293,7 +293,7 @@ static int comp_specific_builder(struct sof_ipc_comp *comp,
 		if (IPC_TAIL_IS_SIZE_INVALID(*proc))
 			return -EBADMSG;
 
-		if (proc->comp.hdr.size + proc->comp.ext_data_length > SOF_IPC_MSG_MAX_SIZE)
+		if (proc->comp.hdr.size + proc->size > SOF_IPC_MSG_MAX_SIZE)
 			return -EBADMSG;
 
 		config->process.type = proc->type;