Fix wrong ifdef in lapi/fs.h

This fixes compilation in the cases where struct file_clone_range is
defined in system headers. The problem was that the
HAVE_FILE_CLONE_RANGE should have been HAVE_STRUCT_FILE_CLONE_RANGE.

Fixes: 3acc96d ("Add fallback definitions for lapi/fs.h")
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>

include/lapi/fs.h

@@ -21,7 +21,7 @@
 #include <stdint.h>
 #include "lapi/abisize.h"
 
-#ifndef HAVE_FILE_CLONE_RANGE
+#ifndef HAVE_STRUCT_FILE_CLONE_RANGE
 struct file_clone_range {
 	int64_t src_fd;
 	uint64_t src_offset;