depends.mk: fix typo in rdep function

Just like later in the file,
the precursor to <stampfile>_check
<stampfile>_check.1 is supposed to be moved to
<stampfile>_check before it is touched.

This line would error if it was ever run.

Signed-off-by: Michael Pratt <mcpratt@pm.me>

include/depends.mk

@@ -27,7 +27,7 @@ ifneq ($(wildcard $(2)),)
 		{ [ \! -f "$(3)" ] || diff $(3) $(3).1 >/dev/null; } && \
 	) \
 	{ \
-		[ -f "$(2)_check.1" ] && mv "$(2)_check.1"; \
+		[ -f "$(2)_check.1" ] && mv "$(2)_check.1" "$(2)_check"; \
 	    $(TOPDIR)/scripts/timestamp.pl $(DEP_FINDPARAMS) $(4) -n $(2) $(1) && { \
 			$(call debug_eval,$(SUBDIR),r,echo "No need to rebuild $(2)";) \
 			touch -r "$(2)" "$(2)_check"; \