split: use xopen_stdin()

function                                             old     new   delta
split_main                                           558     543     -15

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/split.c b/coreutils/split.c
index e401bd3..db5a172 100644
--- a/coreutils/split.c
+++ b/coreutils/split.c
@@ -82,9 +82,7 @@
 		int fd;
 		if (argv[1])
 			sfx = argv[1];
-		fd = open_or_warn_stdin(argv[0]);
-		if (fd == -1)
-			return EXIT_FAILURE;
+		fd = xopen_stdin(argv[0]);
 		xmove_fd(fd, STDIN_FILENO);
 	} else {
 		argv[0] = (char *) bb_msg_standard_input;