Do not reapply linux patches if LINUX26_PATCH_SOURCE is empty, and we are continuing building after a failure

target/linux/Makefile.in.advanced

@@ -71,7 +71,11 @@ LINUX26_PATCH_SITE:=$(strip $(subst ",,$(BR2_KERNEL_PATCH_SITE)))
 LINUX26_BSP_PATCH:=$(strip $(subst ",,$(BR2_LINUX_BSP_PATCH)))
 #"))
 
-LINUX_HEADERS_DEPENDS:= $(DL_DIR)/$(LINUX26_PATCH_SOURCE) $(LINUX26_BSP_PATCH)
+LINUX_HEADERS_DEPENDS:=  $(LINUX26_BSP_PATCH)
+
+ifneq ($(LINUX26_PATCH_SOURCE),)
+LINUX_HEADERS_DEPENDS+=$(DL_DIR)/$(LINUX26_PATCH_SOURCE)
+endif
 
 # ------------------------------------
 # kernel patches provided by buildroot