x86/build: Remove the left-over bzlilo target

Commit

  f279b49f ("x86/boot: Modernize genimage script; hdimage+EFI support")

removed the bzlilo target from arch/x86/boot/Makefile.

Remove the left-over from arch/x86/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210729140023.442101-1-masahiroy@kernel.org