staging/lustre/libcfs: remove unused portal_enter_debugger variable

Remove portal_enter_debugger because it's not used any more.
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/libcfs/debug.c

@@ -215,9 +215,6 @@ EXPORT_SYMBOL(libcfs_debug_binary);
 unsigned int libcfs_stack = 3 * THREAD_SIZE / 4;
 EXPORT_SYMBOL(libcfs_stack);
 
-static unsigned int portal_enter_debugger;
-EXPORT_SYMBOL(portal_enter_debugger);
-
 unsigned int libcfs_catastrophe;
 EXPORT_SYMBOL(libcfs_catastrophe);