io_uring_enter: don't expose sigset_size argument

Applications should not need to care about this, we can pass it in
ourselves. Once the libc support is there, we won't expose this
parameter either.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

src/liburing.h

@@ -47,7 +47,7 @@ struct io_uring {
  */
 extern int io_uring_setup(unsigned entries, struct io_uring_params *p);
 extern int io_uring_enter(unsigned fd, unsigned to_submit,
-	unsigned min_complete, unsigned flags, sigset_t *sig, size_t sigsz);
+	unsigned min_complete, unsigned flags, sigset_t *sig);
 extern int io_uring_register(int fd, unsigned int opcode, void *arg,
 	unsigned int nr_args);