i915: Fix most of the clear problems

trivial/clear-undefined still fails

src/gallium/drivers/i915simple/i915_clear.c

@@ -44,4 +44,5 @@ i915_clear(struct pipe_context *pipe, struct pipe_surface *ps,
 	   unsigned clearValue)
 {
    pipe->surface_fill(pipe, ps, 0, 0, ps->width, ps->height, clearValue);
+   ps->status = PIPE_SURFACE_STATUS_DEFINED;
 }

src/gallium/drivers/i915simple/i915_texture.c

@@ -635,6 +635,7 @@ i915_get_tex_surface(struct pipe_screen *screen,
       ps->pitch = tex->pitch;
       ps->offset = offset;
       ps->usage = flags;
+      ps->status = PIPE_SURFACE_STATUS_DEFINED;
    }
    return ps;
 }