sched/deadline: Delete extraneous extern for to_ratio()

There was a prototype for it added to kernel/sched/sched.h
at the same time the extern was added, so the extern in
the C file was never really ever needed.

See commit 332ac17e
("sched/deadline: Add bandwidth management for SCHED_DEADLINE
tasks") for details.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dario Faggioli <raistlin@linux.it>
Link: http://lkml.kernel.org/r/1400013605-18717-1-git-send-email-paul.gortmaker@windriver.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/deadline.c

@@ -57,8 +57,6 @@ void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime)
 	dl_b->dl_runtime = runtime;
 }
 
-extern unsigned long to_ratio(u64 period, u64 runtime);
-
 void init_dl_bw(struct dl_bw *dl_b)
 {
 	raw_spin_lock_init(&dl_b->lock);