images/Makefile: fix dep gen

Since this part is inside "define" statement, double $ should be
used to refer to internal functions, to call the patsubst when
a define is called (rather than defined).

This should fix dependency generation for images/
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>

images/Makefile

@@ -92,7 +92,7 @@ ifeq ($(PROTOUFIX),y)
 endif
 $(obj)/$(1).pb-c.d: $(obj)/$(1).pb-c.c $(addsuffix .pb-c.d,$(addprefix $(obj)/,$(2))) $(makefile-deps)
 	$$(E) "  DEP     " $$@
-	$$(Q) $$(CC) -M -MT $$@ -MT $(patsubst %.d,%.o,$$@) $$(CFLAGS) $$< -o $$@
+	$$(Q) $$(CC) -M -MT $$@ -MT $$(patsubst %.d,%.o,$$@) $$(CFLAGS) $$< -o $$@
 endef
 
 $(foreach file, $(proto-obj-y),                                                 \