board: mediatek: rename pumpkin board into mt8516

More than one pumpkin board has been made with different MediaTek SoCs.
Rename the pumpkin board to follow the naming convention of all
other MediaTek boards and also to not be confusing when other pumpkin
boards will be added in follow-up commits.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
diff --git a/include/configs/pumpkin.h b/include/configs/mt8516.h
similarity index 96%
rename from include/configs/pumpkin.h
rename to include/configs/mt8516.h
index 9c52cae..e809a9c 100644
--- a/include/configs/pumpkin.h
+++ b/include/configs/mt8516.h
@@ -6,8 +6,8 @@
  * Author: Fabien Parent <fparent@baylibre.com
  */
 
-#ifndef __PUMPKIN_H
-#define __PUMPKIN_H
+#ifndef __MT8516_H
+#define __MT8516_H
 
 #include <linux/sizes.h>