arm64: enable more compressed Image formats

Plumb up Makefile arguments for the already supported formats in the kbuild
system: lz4, bzip2, lzma, and lzo.

Note that just as with Image.gz, these images are not self-decompressing and
the booting firmware still needs to handle decompression before launching the
kernel image.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/Makefile

@@ -58,7 +58,10 @@ all:	$(KBUILD_IMAGE) $(KBUILD_DTBS)
 
 boot := arch/arm64/boot
 
-Image Image.gz: vmlinux
+Image: vmlinux
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+
+Image.%: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
 zinstall install: vmlinux

arch/arm64/boot/Makefile

@@ -19,9 +19,21 @@ targets := Image Image.gz
 $(obj)/Image: vmlinux FORCE
 	$(call if_changed,objcopy)
 
+$(obj)/Image.bz2: $(obj)/Image FORCE
+	$(call if_changed,bzip2)
+
 $(obj)/Image.gz: $(obj)/Image FORCE
 	$(call if_changed,gzip)
 
+$(obj)/Image.lz4: $(obj)/Image FORCE
+	$(call if_changed,lz4)
+
+$(obj)/Image.lzma: $(obj)/Image FORCE
+	$(call if_changed,lzma)
+
+$(obj)/Image.lzo: $(obj)/Image FORCE
+	$(call if_changed,lzo)
+
 install: $(obj)/Image
 	$(CONFIG_SHELL) $(srctree)/$(src)/install.sh $(KERNELRELEASE) \
 	$(obj)/Image System.map "$(INSTALL_PATH)"