net: ipv6: Fix lladdr state set to a wrong value

The line below is wrong and useless:
	lladdr->state = ADDR_AUTOCONF;

Indeed the three possible values for the state attribute are:
ADDR_TENTATIVE, ADDR_PREFERRED or ADDR_DEPRECATED. ADDR_AUTOCONF
is one possible value for the type attribute.

Moreover uip_ds6_set_lladdr already set the type attribute to
ADDR_AUTOCONF (this done through the call to the function
uip_ds6_addr_add).

Therefore this issue has been simply fixed by removing the line.

Change-Id: I432b7bb6a6a858264bb634f2e4d253f55acbbd5b
Signed-off-by: Sebastien Griffoul <sebastien.griffoul@intel.com>