src/soc/samsung: Remove unused <stdlib.h>

Change-Id: I6a933295de7c41d62e6a95f955c098b49ea17f08
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33689
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/samsung/exynos5420/cpu.c

@@ -24,7 +24,6 @@
 #include <soc/cpu.h>
 #include <soc/clk.h>
 #include <stddef.h>
-#include <stdlib.h>
 #include <string.h>
 
 #include "chip.h"