microblaze: Add linux.bin.ub target

Currently the linux.bin target creates both linux.bin and linux.bin.ub.
Add linux.bin.ub as separate target to generate linux.bin.ub.

Signed-off-by: Jason Wu <huanyu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/microblaze/Makefile b/arch/microblaze/Makefile
index 0a603d3..40350a3 100644
--- a/arch/microblaze/Makefile
+++ b/arch/microblaze/Makefile
@@ -72,7 +72,7 @@
 archclean:
 	$(Q)$(MAKE) $(clean)=$(boot)
 
-linux.bin linux.bin.gz: vmlinux
+linux.bin linux.bin.gz linux.bin.ub: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
 simpleImage.%: vmlinux
@@ -81,6 +81,7 @@
 define archhelp
   echo '* linux.bin    - Create raw binary'
   echo '  linux.bin.gz - Create compressed raw binary'
+  echo '  linux.bin.ub - Create U-Boot wrapped raw binary'
   echo '  simpleImage.<dt> - ELF image with $(arch)/boot/dts/<dt>.dts linked in'
   echo '                   - stripped elf with fdt blob'
   echo '  simpleImage.<dt>.unstrip - full ELF image with fdt blob'