i965: Delete brw_wm_prog_key::render_to_fbo and drawable_height.

Now that we handle flipping and other gl_FragCoord transformations
via a uniform, these key fields have no users.

This patch actually eliminates the associated recompiles.  The Tomb
Raider benchmark's minimum FPS increases from ~1 FPS to a reasonable
number.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/intel/vulkan/anv_pipeline.c

@@ -272,10 +272,6 @@ populate_wm_prog_key(const struct brw_device_info *devinfo,
    /* XXX Vulkan doesn't appear to specify */
    key->clamp_fragment_color = false;
 
-   /* Vulkan always specifies upper-left coordinates */
-   key->drawable_height = 0;
-   key->render_to_fbo = false;
-
    if (extra && extra->color_attachment_count >= 0) {
       key->nr_color_regions = extra->color_attachment_count;
    } else {