commonlib: list: Include <stdint.h>

The list macros use uintptr_t, so they need to include the header that
declares it.

Change-Id: I56b2a988bb11d40c8761717bcd02a8199c077046
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81288
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/commonlib/include/commonlib/list.h

@@ -5,6 +5,7 @@
 #define __COMMONLIB_LIST_H__
 
 #include <commonlib/helpers.h>
+#include <stdint.h>
 
 struct list_node {
 	struct list_node *next;