x86: fix padding in images

The previous rework of x86 image creation done in commit  cb007a7bf619
("x86: switch image generation to new code") broke the padding in
images.

 sda: p2 size 212992 extends beyond EOD, enabling native capacity
 sda: p2 size 212992 extends beyond EOD, truncated
 sd 0:0:0:0: [sda] Attached SCSI disk
 SQUASHFS error: squashfs_read_data failed to read block 0x2cc556
 unable to read id index table
 VFS: Cannot open root device "PARTUUID=ac5c9cd8-02" or unknown-block(8,2): error -5
 Please append a correct "root=" boot option; here are the available partitions:
 0800           19761 sda
  driver: sd
   0801           16384 sda1 ac5c9cd8-01

   0802            2865 sda2 ac5c9cd8-02

 Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,2)

Tested with x86/64 with Docker (squashfs), qemustart (ext4/squashfs) and
virtualbox (ext4/squashfs).

Ref: FS#2935
Fixes: cb007a7bf619 ("x86: switch image generation to new code")
Suggested-by: Russell Senior <[email protected]>
Signed-off-by: Paul Spooren <[email protected]>
[commit subject and description tweaks]
Signed-off-by: Petr Štetiar <[email protected]>

target/linux/x86/image/Makefile

@@ -47,7 +47,7 @@ BOOTOPTS:=$(call qstrip,$(CONFIG_GRUB_BOOTOPTS))
 define Build/combined
 	$(CP) $(KDIR)/$(KERNEL_NAME) [email protected]/boot/vmlinuz
 	-$(CP) $(STAGING_DIR_ROOT)/boot/. [email protected]/boot/
-	PADDING="$(CONFIG_TARGET_IMAGES_PAD)" SIGNATURE="$(IMG_PART_SIGNATURE)" $(SCRIPT_DIR)/gen_image_generic.sh \
+	PADDING="1" SIGNATURE="$(IMG_PART_SIGNATURE)" $(SCRIPT_DIR)/gen_image_generic.sh \
 		$@ \
 		$(CONFIG_TARGET_KERNEL_PARTSIZE) [email protected] \
 		$(CONFIG_TARGET_ROOTFS_PARTSIZE) $(IMAGE_ROOTFS) \
@@ -95,10 +95,10 @@ endef
 DEVICE_VARS += GRUB2_VARIANT
 define Device/Default
   ARTIFACT/image.iso := grub-config iso | iso
-  IMAGE/combined.img := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install
-  IMAGE/combined.img.gz := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | gzip
-  IMAGE/combined.vdi := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | qemu-image vdi
-  IMAGE/combined.vmdk := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | qemu-image vmdk
+  IMAGE/combined.img := grub-config pc | combined | grub-install
+  IMAGE/combined.img.gz := grub-config pc | combined | grub-install | gzip
+  IMAGE/combined.vdi := grub-config pc | combined | grub-install | qemu-image vdi
+  IMAGE/combined.vmdk := grub-config pc | combined | grub-install | qemu-image vmdk
   ifeq ($(CONFIG_TARGET_IMAGES_GZIP),y)
     IMAGES := combined.img.gz
   else