x86: image: drop dead code

These are remnants of old image generation code, which now serve no
purpose.
Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>

target/linux/x86/image/Makefile

@@ -13,12 +13,6 @@ GRUB_SERIAL_CONFIG =
 GRUB_TERMINAL_CONFIG =
 GRUB_CONSOLE_CMDLINE =
 
-ifneq ($(strip $(foreach subtarget,$(USE_ATKBD),$(CONFIG_TARGET_x86_$(subtarget)))),)
-  GRUB2_VARIANT := generic
-else
-  GRUB2_VARIANT := legacy
-endif
-
 ifneq ($(CONFIG_GRUB_CONSOLE),)
   GRUB_CONSOLE_CMDLINE += console=tty0
   GRUB_TERMINALS += console
@@ -152,8 +146,6 @@ define Device/Default
   ARTIFACTS := $$(ARTIFACTS-y)
 endef
 
-$(eval $(call Image/gzip-ext4-padded-squashfs))
-
 ifeq ($(SUBTARGET),64)
   include 64.mk
 endif