arm64: vdso: fix makefile dependency on vdso.so

There is currently no dependency for vdso*-wrap.S on vdso*.so, which means that
you can get a build that uses a stale vdso*-wrap.o.

In commit a5b8ca9, the file that includes the vdso.so was moved and renamed
from arch/arm64/kernel/vdso/vdso.S to arch/arm64/kernel/vdso-wrap.S, when this
happened the Makefile was not updated to force the dependcy on vdso.so.

Fixes: a5b8ca9 ("arm64: do not descend to vdso directories twice")
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220510102721.50811-1-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/kernel/Makefile

@@ -75,6 +75,10 @@ obj-$(CONFIG_ARM64_MTE)			+= mte.o
 obj-y					+= vdso-wrap.o
 obj-$(CONFIG_COMPAT_VDSO)		+= vdso32-wrap.o
 
+# Force dependency (vdso*-wrap.S includes vdso.so through incbin)
+$(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
+$(obj)/vdso32-wrap.o: $(obj)/vdso32/vdso.so
+
 obj-y					+= probes/
 head-y					:= head.o
 extra-y					+= $(head-y) vmlinux.lds

arch/arm64/kernel/vdso/Makefile

@@ -52,9 +52,6 @@ GCOV_PROFILE := n
 targets += vdso.lds
 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 
-# Force dependency (incbin is bad)
-$(obj)/vdso.o : $(obj)/vdso.so
-
 # Link rule for the .so file, .lds has to be first
 $(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
 	$(call if_changed,vdsold_and_vdso_check)

arch/arm64/kernel/vdso32/Makefile

@@ -131,9 +131,6 @@ obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso)
 targets += vdso.lds
 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 
-# Force dependency (vdso.s includes vdso.so through incbin)
-$(obj)/vdso.o: $(obj)/vdso.so
-
 include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE
 	$(call if_changed,vdsosym)