[PATCH v2] winemac: Handle dummy_surface in get_mac_surface.

[Piotr Caban]

Signed-off-by: Piotr Caban <piotr(a)codeweavers.com>
---
  dlls/winemac.drv/surface.c | 13 ++++++++-----
  1 file changed, 8 insertions(+), 5 deletions(-)