test: Add a simple test to detected warnings with uint64_t, uintptr_t

These types are problematic because they are typically declared in a
non-standard way in U-Boot. For example, U-Boot uses 'long long' for
int64_t even on a 64-bit machine whereas stdint.h uses 'long'.
Similarly, U-Boot always uses 'long' for intptr_t whereas stdint.h mostly
uses 'int'.

This simple test script runs a few toolchains on a few archs to check for
warnings.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/stdint/int-types.c

@@ -0,0 +1,13 @@
+#include <common.h>
+#include <inttypes.h>
+
+int test_types(void)
+{
+	uintptr_t uintptr = 0;
+	uint64_t uint64 = 0;
+	u64 u64_val = 0;
+
+	printf("uintptr = %" PRIuPTR "\n", uintptr);
+	printf("uint64 = %" PRIu64 "\n", uint64);
+	printf("u64 = %" PRIu64 "\n", u64_val);
+}