GL4: Fix incorrectly calculating the base offset for IssueCopy
GL4: Fix incorrectly calculating the base offset for IssueCopy

sephiroth99/xenia,ObsidianGuardian/xenia,sabretooth/xenia,ObsidianGuardian/xenia,sephiroth99/xenia,maxton/xenia,maxton/xenia,maxton/xenia,sephiroth99/xenia,sabretooth/xenia,ObsidianGuardian/xenia,sabretooth/xenia