For updating broadcast register, read the current value from unicast register. JIRA GPUT19x-75 Change-Id: Ib4a3791304cabe77cf46543d4bec0312c6fcc0fb Signed-off-by: Seema Khowala <seemaj@nvidia.com> Reviewed-on: https://git-master/r/1511735 Reviewed-by: Automatic_Commit_Validation_User GVS: Gerrit_Virtual_Submit Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>