ARM: 8557/1: specify install, zinstall, and uinstall as PHONY targets

Obviously, these are PHONY targets.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/boot/Makefile

@@ -88,7 +88,7 @@ $(obj)/bootpImage: $(obj)/bootp/bootp FORCE
 	$(call if_changed,objcopy)
 	@$(kecho) '  Kernel: $@ is ready'
 
-PHONY += initrd
+PHONY += initrd install zinstall uinstall
 initrd:
 	@test "$(INITRD_PHYS)" != "" || \
 	(echo This machine does not support INITRD; exit -1)