Introduce prototype-style function definitions for
__pthread_rwlock_rdlock, __pthread_rwlock_wrlock.  Upstream did this as
part of:

commit a832bdd36203fcb37fa5ad25200ef3c1ae205efe
Author: Andi Kleen <ak@linux.intel.com>
Date:   Mon Mar 17 05:48:28 2014 -0700

    Add a fast path for C rd/wrlock v2

diff --git a/nptl/pthread_rwlock_rdlock.c b/nptl/pthread_rwlock_rdlock.c
index 2c176c7cb9ab4b7f..4c397d784b82a510 100644
--- a/nptl/pthread_rwlock_rdlock.c
+++ b/nptl/pthread_rwlock_rdlock.c
@@ -26,8 +26,7 @@
 
 /* Acquire read lock for RWLOCK.  */
 int
-__pthread_rwlock_rdlock (rwlock)
-     pthread_rwlock_t *rwlock;
+__pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
 {
   int result = 0;
 
diff --git a/nptl/pthread_rwlock_wrlock.c b/nptl/pthread_rwlock_wrlock.c
index 1476d1370d56475a..3dcc42b774eef8de 100644
--- a/nptl/pthread_rwlock_wrlock.c
+++ b/nptl/pthread_rwlock_wrlock.c
@@ -26,8 +26,7 @@
 
 /* Acquire write lock for RWLOCK.  */
 int
-__pthread_rwlock_wrlock (rwlock)
-     pthread_rwlock_t *rwlock;
+__pthread_rwlock_wrlock (pthread_rwlock_t *rwlock)
 {
   int result = 0;