symbols/arm: don't use symbols-dummy

In particular when linking with lld, which converts hidden symbols to
local ones, the ELF symbol table can change in unhelpful ways between the
first two linking passes, resulting in the .rodata contributions to change
between the 2nd and 3rd pass. That, however, renders our embedded symbol
table pretty much unusable; the recently introduced self-test may then
also fail. (Another difference between compiling a C file and assembling
the generated ones is that - with -fdata-sections in use - the .rodata
contributions move between passes 1 and 2, when we'd prefer them not to.)

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>

xen/arch/arm/Makefile

@@ -85,8 +85,10 @@ ifeq ($(CONFIG_ARM_64),y)
 endif
 
 $(TARGET)-syms: $(objtree)/prelink.o $(obj)/xen.lds
+	$(objtree)/tools/symbols $(all_symbols) --empty > $(dot-target).0.S
+	$(MAKE) $(build)=$(@D) $(dot-target).0.o
 	$(LD) $(XEN_LDFLAGS) -T $(obj)/xen.lds $< \
-	    $(objtree)/common/symbols-dummy.o -o $(dot-target).0
+	      $(dot-target).0.o -o $(dot-target).0
 	$(NM) -pa --format=sysv $(dot-target).0 \
 		| $(objtree)/tools/symbols $(all_symbols) --sysv --sort \
 		> $(dot-target).1.S