[IA64] add vmlinuz target

This is a trivial stand-alone patch out of the Xen/ia64 patches.  Add
a vmlinuz build target to be more compatible with x86-ish targets.
Signed-off-by: NAlex Williamson <alex.williamson@hp.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

arch/ia64/Makefile

@@ -71,6 +71,8 @@ all: compressed unwcheck
 
 compressed: vmlinux.gz
 
+vmlinuz: vmlinux.gz
+
 vmlinux.gz: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $@