tipc: check skb_linearize() return value in tipc_disc_rcv()

If skb_linearize() fails in tipc_disc_rcv(), we need to free the skb instead of
handle it.

Fixes: 25b0b9c4

 ("tipc: handle collisions of 32-bit node address hash values")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Link: https://lore.kernel.org/r/20221119072832.7896-1-yuehaibing@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>