zebra: fix evpn rmac nh list cmp function

zebra: fix evpn rmac nh list cmp function

EVPN RMAC (Router MAC) nexthop list compare
function needs to return all values so
the list element can be compared and added/deleted
properly.

Ticket:#3486989
Testing Done:
Originate EVPN Type-5 route with PIP IP and MAC as remote
nexthops.
Change the PIP IP address which triggers nexthop change.

Before fix:
When PIP IP changes RMAC is deleted from remote VTEPs.

TORS1# show evpn next-hops vni 4001 | include 00:02:00:00:00:2d
27.0.0.11       00:02:00:00:00:2d
TORS1# show evpn rmac vni 4001 | include 00:02:00:00:00:2d
00:02:00:00:00:2d 27.0.0.11

----- Remote VTEP change nexthop IP to 172.16.16.16 -----

TORS1# show evpn next-hops vni 4001 | include 00:02:00:00:00:2d
172.16.16.16    00:02:00:00:00:2d
TORS1# show evpn rmac vni 4001 | include 00:02:00:00:00:2d
TORS1#

After fix:
RMAC is retained as its nexthop list is not empty,
thus it is not deleted from remote VTEPs.

TORS1# show evpn rmac vni 4001 | include 00:02:00:00:00:2d
00:02:00:00:00:2d 172.16.16.16

Log:
2023/06/27 00:50:36.833474 ZEBRA: [XREH0-ZYMH6] L3VNI 4001 Remote VTEP
change(27.0.0.11 -> 172.16.16.16) for RMAC 00:02:00:00:00:2d

Signed-off-by: Chirag Shah <chirag@nvidia.com>
(cherry picked from commit a7d77ee58bdcc7dfaccfb124d94f738f2b2b4696)