build: fix dependencies for files compiled from their parent directory

The use of $(basename ...) here was wrong (yet I'm sure I tested it).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

xen/Rules.mk

@@ -105,7 +105,7 @@ include Makefile
 DEPS = .*.d
 define gendep
     ifneq ($(1),$(subst /,:,$(1)))
-        DEPS += $(dir $(1)).$(basename $(notdir $(1))).d
+        DEPS += $(dir $(1)).$(notdir $(1)).d
     endif
 endef
 $(foreach o,$(filter-out %/,$(obj-y)),$(eval $(call gendep,$(o))))