arch: decompressor: remove useless vmlinux.bin.all-y

Presumably, arch/{parisc,s390,sh}/boot/compressed/Makefile copied
arch/x86/boot/compressed/Makefile, but vmlinux.bin.all-y is useless
here because it is the same as $(obj)/vmlinux.bin.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>