sched: fix cpupri priocount

A rounding error was pointed out by Peter Zijlstra which would result
in the structure holding priorities to be off by one.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/sched_cpupri.h

@@ -4,7 +4,7 @@
 #include <linux/sched.h>
 
 #define CPUPRI_NR_PRIORITIES 2+MAX_RT_PRIO
-#define CPUPRI_NR_PRI_WORDS CPUPRI_NR_PRIORITIES/BITS_PER_LONG
+#define CPUPRI_NR_PRI_WORDS (CPUPRI_NR_PRIORITIES + BITS_PER_LONG/2)/BITS_PER_LONG
 
 #define CPUPRI_INVALID -1
 #define CPUPRI_IDLE     0