d3d9: Call wined3d_swapchain_get_front_buffer_data instead of wined3d_device_get_front_buffer_data in d3d9_device_GetFrontBuffer.

Removed the now unused wined3d_device_get_front_buffer_data from wined3d.
Signed-off-by: Riccardo Bortolato <rikyz619@gmail.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>