tree: Drop unused <stdlib.h>

Change-Id: Ie7e36cfa5a09d94bb58f12f9bd262255a630424c
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81819
Reviewed-by: Yidi Lin <yidilin@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/lib/bootsplash.c

@@ -5,7 +5,6 @@
 #include <console/console.h>
 #include <endian.h>
 #include <bootsplash.h>
-#include <stdlib.h>
 
 #include "jpeg.h"