src/cpu: Use 'include <stdlib.h>' when appropriate

Change-Id: I44346594bc106eed73a1268b82f026b69e5f4512
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32821
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/intel/haswell/finalize.c

@@ -15,7 +15,6 @@
  */
 
 #include <stdint.h>
-#include <stdlib.h>
 #include <arch/cpu.h>
 #include <cpu/x86/msr.h>
 #include "haswell.h"