eigen: fix dont build if lib is not selected

Author: cirosantilli

kernel_module/user/Makefile

@@ -15,7 +15,7 @@ ifeq ($(BR2_PACKAGE_EIGEN),y)
 	# http://lists.busybox.net/pipermail/buildroot/2018-June/222914.html
 	#CXXFLAGS_EXTRA += $(shell $(PKG_CONFIG) --cflags eigen3)
 else
-	OUTS := $(filter-out eigen_%$(OUT_EXT),$(OUTS))
+	OUTS := $(filter-out eigen%$(OUT_EXT),$(OUTS))
 endif
 ifeq ($(BR2_PACKAGE_LIBDRM),y)
 	LIBS += $(shell $(PKG_CONFIG) --libs libdrm)