i965: Add support for sampling from XYUV images

Add support to the i965 DRI driver to sample from XYUV8888 buffers.

Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>

src/intel/compiler/brw_compiler.h

@@ -196,6 +196,7 @@ struct brw_sampler_prog_key_data {
    uint32_t yx_xuxv_image_mask;
    uint32_t xy_uxvx_image_mask;
    uint32_t ayuv_image_mask;
+   uint32_t xyuv_image_mask;
 
    /* Scale factor for each texture. */
    float scale_factors[32];