ieee1905: add missing NULL terminatator to ieee1905_reporting_policy_flags[].

ieee1905: add missing NULL terminatator to ieee1905_reporting_policy_flags[].

Add missing NULL terminator to ieee1905_reporting_policy_flags[], in order to fix buffer overflow.

ASAN report:

ERROR: AddressSanitizer: global-buffer-overflow on address 0x0000092a4af8 at pc 0x00000062afd2 bp 0x7ffce7e468d0 sp 0x7ffce7e468c8
READ of size 8 at 0x0000092a4af8 thread T0
    #0 0x62afd1 in proto_item_add_bitmask_tree /src/wireshark/epan/proto.c:10406:9
    #1 0x62953f in proto_tree_add_bitmask_with_flags /src/wireshark/epan/proto.c:10786:3
    #2 0xfb8271 in dissect_metric_reporting_policy /src/wireshark/epan/dissectors/packet-ieee1905.c:2762:9
    #3 0xfb2997 in dissect_ieee1905_tlv_data /src/wireshark/epan/dissectors/packet-ieee1905.c:4390:18
    #4 0xfb23c8 in dissect_ieee1905 /src/wireshark/epan/dissectors/packet-ieee1905.c:4577:18

Found by oss-fuzz/5298.

Change-Id: I35dbd6d29d0a3a5560286146fbed172c810e5b2d
Link: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5298
Reviewed-on: https://code.wireshark.org/review/25520
Petri-Dish: Jakub Zawadzki <darkjames-ws@darkjames.pl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Jakub Zawadzki <darkjames-ws@darkjames.pl>