fix: libc: use long for 64-bit types on aarch64

Use long instead of long long on aarch64 for 64_t stdint types.
Introduce inttypes.h to properly support printf format specifiers for
fixed width types for such change.

Change-Id: I0bca594687a996fde0a9702d7a383055b99f10a1
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
diff --git a/include/lib/libc/aarch64/stdint_.h b/include/lib/libc/aarch64/stdint_.h
new file mode 100644
index 0000000..56e9f1b
--- /dev/null
+++ b/include/lib/libc/aarch64/stdint_.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2020 Broadcom
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+/*
+ * Portions copyright (c) 2020, ARM Limited and Contributors.
+ * All rights reserved.
+ */
+
+#ifndef STDINT__H
+#define STDINT__H
+
+#define INT64_MAX  LONG_MAX
+#define INT64_MIN  LONG_MIN
+#define UINT64_MAX ULONG_MAX
+
+#define INT64_C(x) x ## L
+#define UINT64_C(x) x ## UL
+
+typedef long int64_t;
+typedef unsigned long uint64_t;
+typedef long int64_least_t;
+typedef unsigned long uint64_least_t;
+typedef long int64_fast_t;
+typedef unsigned long uint64_fast_t;
+
+typedef __int128 int128_t;
+typedef unsigned __int128 uint128_t;
+
+#endif