fix(vsock): remove redundant buffer check

[mpojmaj]

Drop the check from Packet::check and rely on the existing check in recv_packet_connected, which already validates the payload against the buffer it was read into

MigTD/src/devices/vsock/src/stream.rs

Lines 389 to 393 in f4b93e4

	if packet.data_len() as usize <= recv.len() {
	recv.truncate(packet.data_len() as usize);
	} else {
	return Err(VsockError::Illegal);
	}

This is the real trust boundary; the protocol.rs addition is redundant as well as incorrect for the split header/payload path.