rcu: Remove unused macros from rcupdate.h

ulong2long, USHORT_CMP_GE and USHORT_CMP_LT are redundant and have been
unused for quite a few releases.
Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>

include/linux/rcupdate.h

@@ -34,9 +34,6 @@
 
 #define ULONG_CMP_GE(a, b)	(ULONG_MAX / 2 >= (a) - (b))
 #define ULONG_CMP_LT(a, b)	(ULONG_MAX / 2 < (a) - (b))
-#define ulong2long(a)		(*(long *)(&(a)))
-#define USHORT_CMP_GE(a, b)	(USHRT_MAX / 2 >= (unsigned short)((a) - (b)))
-#define USHORT_CMP_LT(a, b)	(USHRT_MAX / 2 < (unsigned short)((a) - (b)))
 
 /* Exported common interfaces */
 void call_rcu(struct rcu_head *head, rcu_callback_t func);