drm/radeon/kms/atom: fix some parser bugs

- add support for inline src params
- fix shift_left/shift_right and shl/shr ops
  shift_* ops use inline src params, shl/r use full params
- fix mask op (uses inline params)

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>