networkd: networkd: ndisc set SO_BINDTODEVICE on socket (#3294)

networkd: networkd: ndisc set SO_BINDTODEVICE on socket (#3294)

From the issue #2004 we are receiving packet even if this
packet is not intended for this interface.

This can be reproduced.

lp3s0: Updating address: 2001:db8:1:0:7e7a:91ff:fe6d:ffe2/64 (valid for 1d)
wlp3s0: Updating address: fe80::7e7a:91ff:fe6d:ffe2/64 (valid forever)
NDisc CLIENT: Received RA from non-link-local address ::. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 6. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 3. Ignoring.
enp0s25: Updating address: 2001:db8:1:0:2ad2:44ff:fe6a:ae07/64 (valid for 1d)
enp0s25: Updating address: fe80::2ad2:44ff:fe6a:ae07/64 (valid forever)
NDisc CLIENT: Sent Router Solicitation
NDisc CLIENT: Sent Router Solicitation
NDisc CLIENT: Sent Router Solicitation
NDisc CLIENT: Received RA on wrong interface: 3 != 2. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 3 != 6. Ignoring.
NDisc CLIENT: Received RA from non-link-local address ::. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 6. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 3. Ignoring.
enp0s25: Updating address: 2001:db8:1:0:2ad2:44ff:fe6a:ae07/64 (valid for 1d)
enp0s25: Updating address: fe80::2ad2:44ff:fe6a:ae07/64 (valid forever)

Add SO_BINDTODEVICE to socket
fixes #2004