microblaze: Fix makefile to work with latest toolchain

commit 00708d42 upstream.

When building with latest binutils, vmlinux includes
some sections which need to be stripped out when building
the binary image.
Signed-off-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/microblaze/boot/Makefile

@@ -8,7 +8,7 @@ obj-y += linked_dtb.o
 
 targets := linux.bin linux.bin.gz simpleImage.%
 
-OBJCOPYFLAGS := -O binary
+OBJCOPYFLAGS := -R .note -R .comment -R .note.gnu.build-id -O binary
 
 # Ensure system.dtb exists
 $(obj)/linked_dtb.o: $(obj)/system.dtb