build: drop UBI EOF marker from images by default

Only add them where they are actually required.
Should help with compatibility issues with stock U-Boot images that
access UBI

Signed-off-by: Felix Fietkau <nbd@nbd.name>

include/image.mk

@@ -353,7 +353,7 @@ define Device/Init
   PAGESIZE :=
   SUBPAGESIZE :=
   VID_HDR_OFFSET :=
-  UBINIZE_OPTS := -E 5
+  UBINIZE_OPTS :=
   UBINIZE_PARTS :=
   MKUBIFS_OPTS :=