src/southbridge: Remove unused <stdlib.h>

Change-Id: I5728b44fdd680b21e951397a2390e24f9171ac34
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32829
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/southbridge/amd/agesa/hudson/spi.c

@@ -13,7 +13,6 @@
  * GNU General Public License for more details.
  */
 #include <stdint.h>
-#include <stdlib.h>
 #include <device/mmio.h>
 #include <console/console.h>
 #include <spi_flash.h>