src/include: Remove unused 'include <stdint.h>'

Change-Id: I407474eac9f44f04036af7182714db7fdc4035f1
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43369
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/include/stdbool.h

@@ -3,9 +3,6 @@
 #ifndef __STDBOOL_H__
 #define __STDBOOL_H__
 
-#include <stdint.h>
-
-
 typedef _Bool   bool;
 #define true    1
 #define false   0