superio: Use 'include <stdlib.h>' when appropriate

Change-Id: I55e7b680e128f29a9fd549edfb676e6571330677
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32830
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/superio/nuvoton/nct5104d/superio.c b/src/superio/nuvoton/nct5104d/superio.c
index 40d1200..493e0ce 100644
--- a/src/superio/nuvoton/nct5104d/superio.c
+++ b/src/superio/nuvoton/nct5104d/superio.c
@@ -16,7 +16,7 @@
 
 #include <device/pnp.h>
 #include <superio/conf_mode.h>
-#include <stdlib.h>
+
 #include "nct5104d.h"
 #include "chip.h"
 
diff --git a/src/superio/nuvoton/nct5572d/superio.c b/src/superio/nuvoton/nct5572d/superio.c
index e8249d4..3084687 100644
--- a/src/superio/nuvoton/nct5572d/superio.c
+++ b/src/superio/nuvoton/nct5572d/superio.c
@@ -21,7 +21,6 @@
 #include <device/pnp.h>
 #include <pc80/keyboard.h>
 #include <pc80/mc146818rtc.h>
-#include <stdlib.h>
 #include <arch/acpi.h>
 #include <superio/conf_mode.h>
 
diff --git a/src/superio/nuvoton/nct6776/superio.c b/src/superio/nuvoton/nct6776/superio.c
index e399c0a..78e07b6 100644
--- a/src/superio/nuvoton/nct6776/superio.c
+++ b/src/superio/nuvoton/nct6776/superio.c
@@ -19,7 +19,6 @@
 #include <device/device.h>
 #include <device/pnp.h>
 #include <pc80/keyboard.h>
-#include <stdlib.h>
 #include <superio/conf_mode.h>
 
 #include "nct6776.h"
diff --git a/src/superio/nuvoton/nct6779d/superio.c b/src/superio/nuvoton/nct6779d/superio.c
index 49e6306..7ef3488 100644
--- a/src/superio/nuvoton/nct6779d/superio.c
+++ b/src/superio/nuvoton/nct6779d/superio.c
@@ -20,7 +20,6 @@
 #include <device/device.h>
 #include <device/pnp.h>
 #include <pc80/keyboard.h>
-#include <stdlib.h>
 #include <superio/conf_mode.h>
 
 #include "nct6779d.h"
diff --git a/src/superio/nuvoton/nct6791d/superio.c b/src/superio/nuvoton/nct6791d/superio.c
index 3a6d740..23d5a6f8 100644
--- a/src/superio/nuvoton/nct6791d/superio.c
+++ b/src/superio/nuvoton/nct6791d/superio.c
@@ -21,7 +21,6 @@
 #include <device/device.h>
 #include <device/pnp.h>
 #include <pc80/keyboard.h>
-#include <stdlib.h>
 #include <superio/conf_mode.h>
 
 #include "nct6791d.h"
diff --git a/src/superio/nuvoton/npcd378/superio.c b/src/superio/nuvoton/npcd378/superio.c
index c1f557e..f11e75a 100644
--- a/src/superio/nuvoton/npcd378/superio.c
+++ b/src/superio/nuvoton/npcd378/superio.c
@@ -23,7 +23,6 @@
 #include <device/pnp.h>
 #include <option.h>
 #include <pc80/keyboard.h>
-#include <stdlib.h>
 #include <superio/conf_mode.h>
 #include <arch/acpi.h>
 #include <arch/acpigen.h>
diff --git a/src/superio/nuvoton/wpcm450/superio.c b/src/superio/nuvoton/wpcm450/superio.c
index c666818..aeb394a 100644
--- a/src/superio/nuvoton/wpcm450/superio.c
+++ b/src/superio/nuvoton/wpcm450/superio.c
@@ -17,7 +17,7 @@
 #include <device/device.h>
 #include <device/pnp.h>
 #include <pc80/keyboard.h>
-#include <stdlib.h>
+
 #include "wpcm450.h"
 
 static void init(struct device *dev)