posix: semaphore: use ZRESTRICT

To better handle all possible definitions of restrict
or __restrict keyword and avoid redefinition errors, use
the ZRESTRICT pre-processor defined in toolchain.h

Signed-off-by: Nicholas Lowell <nlowell@lexmark.com>
diff --git a/include/posix/semaphore.h b/include/posix/semaphore.h
index f19c741..e4f5f8c 100644
--- a/include/posix/semaphore.h
+++ b/include/posix/semaphore.h
@@ -14,10 +14,10 @@
 #endif
 
 int sem_destroy(sem_t *semaphore);
-int sem_getvalue(sem_t *restrict semaphore, int *restrict value);
+int sem_getvalue(sem_t *ZRESTRICT semaphore, int *ZRESTRICT value);
 int sem_init(sem_t *semaphore, int pshared, unsigned int value);
 int sem_post(sem_t *semaphore);
-int sem_timedwait(sem_t *restrict semaphore, struct timespec *restrict abstime);
+int sem_timedwait(sem_t *ZRESTRICT semaphore, struct timespec *ZRESTRICT abstime);
 int sem_trywait(sem_t *semaphore);
 int sem_wait(sem_t *semaphore);