During startup, the xfree86 DDX's InitOutput() calls PreInit for
protocol screens first, and then GPU screens. On teardown, dix_main()
calls CloseScreen in the reverse order: GPU screens first starting with
the last one and then working backwards, and then protocol screens also
in reverse order.
InitOutput() calls ScreenInit in the wrong order: for GPU screens first and then
for protocol screens. This causes a problem for drivers that have global state
that is tied to the first screen that calls ScreenInit.
Fix this by simply re-ordering the for loops to call PreInit for
protocol screens first and then for GPU screens second.
(cherry picked from commit e5e9a8ca91)
03b91e17ce