src/{drivers,device,ec}: Remove unused <stdlib.h>

Change-Id: I05422ee4b0aa5c02525ef0b4eccb4dc3ecf871e8
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32822
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/i2c/rtd2132/rtd2132.c

@@ -11,7 +11,6 @@
  * GNU General Public License for more details.
  */
 
-#include <stdlib.h>
 #include <console/console.h>
 #include <delay.h>
 #include <device/device.h>