Add force flag support for PTQM migration.
This flag will be used to allow migration to vdevs which are not
allowed to be selected as primary by using the ini config.
This will be helpful in scenarios where if the current primary link is
going down and peer ptqm needs to be migrated but the partner links of
that mld are the user disabled links for ptqm.
Also add skip_pumac_cnt to mark a link to be skipped from being selected
as new primary
Change-Id: Ia8c7881f37d32211a732c5c7394c4a608099b62a
CRs-Fixed: 3548552
444fa57930