Fix default skeleton path

Signed-off-by: Malte Starostik <m-starostik@versanet.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

Makefile

@@ -271,7 +271,7 @@ STAMP_DIR:=$(BASE_DIR)/stamps
 BINARIES_DIR:=$(BASE_DIR)/images
 TARGET_DIR:=$(BASE_DIR)/target
 TOOLCHAIN_DIR=$(BASE_DIR)/toolchain
-TARGET_SKELETON=$(BASE_DIR)/fs/skeleton
+TARGET_SKELETON=$(TOPDIR)/fs/skeleton
 
 BR2_DEPENDS_DIR=$(BUILD_DIR)/buildroot-config