r600: fix abs for op3 sources

r600: fix abs for op3 sources

If a src was referencing the same temp as the dst, the per-component
copy code didn't work.
e.g.
  cndge r0.xy, r0.xx, |r2|, r3
got expanded into
  mov  r12.x, |r2|
  cndge r0.x, r0.x, r12, r3
  mov  r12.y, |r2|
  cndge r0.y, r0.x, r12, r3
hence for the second cndge r0.x was mistakenly the previous cndge result.
Fix this by doing all the movs first, so there's no bogus alu.last in between.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=102905
Tested-by: <iive@yahoo.com>
Reviewed-by: Dave Airlie <airlied@gmail.com>