Add new scope and address type inlines

[sorry if anyone got these multiple times, git-send-email weirdness]

This set of patches adds new IPv6 scope and address type inlines to both clean-up the code (inspired by Arnaldo's skb cleanup) and reduce calls to ipv6_addr_type() when we can just compare the address directly. No functionality is changed.

I'm only cc'ing the DCCP and LkSCTP lists on the patches that actually touch their code.

-Brian