libc: Import from TF-A

Based on arm-trusted-firware commit 873e394b3bf93214a441f9f98237b58fbbea55aa

Change-Id: I510e092f2b9ff333e9461bdde8d80ed1fab1460c
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
diff --git a/lib/libc/puts.c b/lib/libc/puts.c
new file mode 100644
index 0000000..2a0ca11
--- /dev/null
+++ b/lib/libc/puts.c
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+
+int puts(const char *s)
+{
+	int count = 0;
+
+	while (*s != '\0') {
+		if (putchar(*s) == EOF)
+			return EOF;
+		s++;
+		count++;
+	}
+
+	if (putchar('\n') == EOF)
+		return EOF;
+
+	return count + 1;
+}