[ARM] Remove OP_MAX_COUNTER

OP_MAX_COUNTER never referenced, and is a reminant of an earlier
oprofile implementation.  Remove it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/oprofile/op_counter.h

@@ -10,8 +10,6 @@
 #ifndef OP_COUNTER_H
 #define OP_COUNTER_H
 
-#define OP_MAX_COUNTER 5
-
 /* Per performance monitor configuration as set via
  * oprofilefs.
  */