Add an empty stdint.h file

Some libraries build by U-Boot may include stdint.h. This is not used by
U-Boot itself and causes conflicts with the types defined in
linux/types.h. To work around this, add an empty file with this name so
that it will be used in preference to the compiler version.

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

include/stdint.h

@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Dummy file to allow libraries linked with U-Boot to include stdint.h without
+ * getting the system version.
+ *
+ * U-Boot uses linux types (linux/types.h) so does not make use of stdint.h
+ */