target/target.c: adding keep_alive() to while loop.

Adding the call to keep_alive() to suppress warnings when
running the async flash algorithm. Issue observed when
loading large pieces of code on slower debuggers.

Change-Id: I7660fa05f68ebd7be07b2ca0a55b0f3b6ae718f3
Signed-off-by: Kevin Gillespie <kgills@gmail.com>
Reviewed-on: http://openocd.zylin.com/4686
Tested-by: jenkins
Reviewed-by: Jesse Marroquin
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

src/target/target.c

@@ -1047,6 +1047,9 @@ int target_run_flash_async_algorithm(struct target *target,
 		retval = target_write_u32(target, wp_addr, wp);
 		if (retval != ERROR_OK)
 			break;
+
+		/* Avoid GDB timeouts */
+		keep_alive();
 	}
 
 	if (retval != ERROR_OK) {