crocus/gen4-5: fix ff gs emit on VS vue map change.

This should fix some texturing problems seen on gen4/5, I reproduced it
with a minecraft.trace file

Fixes: f3630548f1 ("crocus: initial gallium driver for Intel gfx 4-7")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11993>

src/gallium/drivers/crocus/crocus_program.c

@@ -1988,6 +1988,8 @@ update_last_vue_map(struct crocus_context *ice,
 
    if (changed_slots || (old_map && old_map->separate != vue_map->separate)) {
       ice->state.dirty |= CROCUS_DIRTY_GEN7_SBE;
+      if (devinfo->ver < 6)
+         ice->state.dirty |= CROCUS_DIRTY_GEN4_FF_GS_PROG;
       ice->state.stage_dirty |= CROCUS_STAGE_DIRTY_UNCOMPILED_FS;
    }