includes: Remove dangling doxygen @}

Change-Id: I05e02f9689c1a6dafb3943657a3db975c2aeacbe
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55592
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

payloads/libpayload/include/stdlib.h

@@ -217,8 +217,6 @@ void exit(int status) __attribute__((noreturn));
 #define halt() do { gdb_enter(); halt(); } while (0)
 #endif
 
-/** @} */
-
 void qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *));
 char *getenv(const char*);
 uint64_t __umoddi3(uint64_t num, uint64_t den);