net: tsec: Fix priv pointer in tsec_mcast_addr()

Access to privlist[1] (hardcoded referece to the 2nd tsec's
priv area) is neither correct nor does it make sense in the
current context.  Each tsec dev has access to its own priv
instance only, and hence to its own set of group address
registers (GADDR) to filter multicast addresses.

This fix leads to removal of the unused (faulty) privlist[]
and related global static vars.  Note that mcast() can be
called only after eth_device allocation and init, and hence
after priv area allocation, so dev->priv is correctly
initialized upon mcast() call.

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Patch: 278990