py/misc.h: Include stdint.h only once (unconditionally at the top).

py/misc.h

@@ -107,7 +107,6 @@ size_t m_get_peak_bytes_allocated(void);
 /** unichar / UTF-8 *********************************************/
 
 #if MICROPY_PY_BUILTINS_STR_UNICODE
-#include <stdint.h> // only include if we need it
 // with unicode enabled we need a type which can fit chars up to 0x10ffff
 typedef uint32_t unichar;
 #else