bpf: Remove xdp_do_flush_map().

xdp_do_flush_map() can be removed because there is no more user in tree.

Remove xdp_do_flush_map().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://lore.kernel.org/r/20230908143215.869913-3-bigeasy@linutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/filter.h

@@ -1025,12 +1025,6 @@ int xdp_do_redirect_frame(struct net_device *dev,
 			  struct bpf_prog *prog);
 void xdp_do_flush(void);
 
-/* The xdp_do_flush_map() helper has been renamed to drop the _map suffix, as
- * it is no longer only flushing maps. Keep this define for compatibility
- * until all drivers are updated - do not use xdp_do_flush_map() in new code!
- */
-#define xdp_do_flush_map xdp_do_flush
-
 void bpf_warn_invalid_xdp_action(struct net_device *dev, struct bpf_prog *prog, u32 act);
 
 #ifdef CONFIG_INET