Netfilter: IRC: Copy nickname to proper address

Fix to copy nickname to address provided by
nickname pointer and avoid overwriting
pointer value.

Change-Id: I8746d8249e807299ae3bec36f6ed9934d8c1628a
Acked-by: Mohit Pahuja <mpahuja@qti.qualcomm.com>
Signed-off-by: Ravinder Konka <rkonka@codeaurora.org>