turnip: remove pre-emption marker

turnip doesn't implement pre-emption, this hasn't been a problem with drm
backend since the kernel driver doesn't implement it either, however this
causes issues with kgsl backend.
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Part-of: <!6994>

src/freedreno/vulkan/tu_cmd_buffer.c

@@ -569,9 +569,6 @@ tu6_emit_tile_select(struct tu_cmd_buffer *cmd,
 {
    const struct tu_framebuffer *fb = cmd->state.framebuffer;
 
-   tu_cs_emit_pkt7(cs, CP_SET_MARKER, 1);
-   tu_cs_emit(cs, A6XX_CP_SET_MARKER_0_MODE(RM6_YIELD));
-
    tu_cs_emit_pkt7(cs, CP_SET_MARKER, 1);
    tu_cs_emit(cs, A6XX_CP_SET_MARKER_0_MODE(RM6_GMEM));