st: Add cubeMapFace parameter to st_finalize_texture.

st: Add cubeMapFace parameter to st_finalize_texture.

st_finalize_texture always accesses image at face 0, but it may not be
set if we are working with cubemap that had other face set.

This fixes crash in piglit
same-attachment-glFramebufferTexture2D-GL_DEPTH_STENCIL_ATTACHMENT.

Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>