printf: add missing cstdint include (#2011)

Since GCC 13 some headers are no longer included transitively through
C++ Standard Library headers.

Signed-off-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

test_conformance/printf/test_printf.cpp

@@ -21,6 +21,7 @@
 #include <algorithm>
 #include <array>
 #include <cstdarg>
+#include <cstdint>
 #include <errno.h>
 #include <memory>
 #include <string.h>