"AMD FirePro W2100" and "AMD Radeon HD 3450" cards not working with the latest version of xorg-x11-drv-ati display drivers

Issue

• HP Z230 with AMD FirePro W2100 graphics card, and some Dell system AMD Radeon HD 3450 is not able to drive display on dual head configuration in RHEL6.8.
• Previously these systems were running RHEL6.7 and dual head configuration was working fine with xorg-x11-drv-ati driver. As soon as the systems were updated to RHEL6.8, it stopped showing display on second monitor.
• The issue is reproducible on a newly installed systems with RHEL6.8.