bgpd: Improve route-map matching for INET(6) AF

bgpd: Improve route-map matching for INET(6) AF

While the current implementation does pay attention to the AF
(inet/inet6) when comparing the IPv4/v6 address against an address-list
/ prefix-list inside a route-map, the AF check is being done rather
late, which leads to CPU cycles being wasted due to unnecessary list
lookups / address matching.

This commit checks the address family of a prefix right inside the
`route_match_ip(v6)_` functions before looking up any address- and/or
prefix-list, which should improve performance.

Signed-off-by: Pascal Mathis <mail@pascalmathis.com>