headers/kernel: Move B_WAIT_TILL_LOADED to a syscall header.

It is only used as an argument to _kern_load_image directly, not to
any of the load_image functions in image.h, so it belongs in a syscall-
specific header like other such constants.

No functional change intended.

headers/os/kernel/image.h

@@ -1,6 +1,6 @@
 /*
- * Copyright 2007-2019, Haiku, Inc. All Rights Reserved.
- * Distributed under the terms of the MIT license.
+ * Copyright 2007-2019, Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
  */
 #ifndef _IMAGE_H
 #define	_IMAGE_H
@@ -67,17 +67,6 @@ typedef struct {
 	/* pointer to a symbol in the callers image */
 
 
-/* flags for _kern_load_image() (private API) */
-enum {
-	B_WAIT_TILL_LOADED	= 0x01,
-		/* Wait till the loader has loaded and relocated (but not yet
-		   initialized) the application image and all dependencies. If not
-		   supplied, the function returns before the loader started to do
-		   anything at all, i.e. it returns success, even if the executable
-		   doesn't exist. */
-};
-
-
 #ifdef __cplusplus
 extern "C" {
 #endif