isl: fix bug where sb.MOCS is not being set

Currently the sb.MOCS is being reset to zero after struct init.

Signed-off-by: sjfricke <spencerfricke@gmail.com>
Fixes: c27fcb1d ("isl: Fill in MOCS for NULL depth, stencil, and HiZ buffers.")
Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <mesa/mesa!17985>

src/intel/isl/isl_emit_depth_stencil.c

@@ -170,7 +170,7 @@ isl_genX(emit_depth_stencil_hiz_s)(const struct isl_device *dev, void *batch,
 #if GFX_VER >= 6
    struct GENX(3DSTATE_STENCIL_BUFFER) sb = {
       GENX(3DSTATE_STENCIL_BUFFER_header),
-      sb.MOCS = info->mocs,
+      .MOCS = info->mocs,
    };
 #else
 #  define sb db