Don't attempt to create 'mkdir' and '-p' directories.

Test: build
Bug: 115920063
Change-Id: I65c60bfe0ca758a4213f10754bc872ea9885ca19
diff --git a/init/Android.mk b/init/Android.mk
index dc400ad..5554995 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -61,9 +61,9 @@
 # Set up the same mount points on the ramdisk that system-as-root contains.
 LOCAL_POST_INSTALL_CMD := \
     mkdir -p $(TARGET_RAMDISK_OUT)/dev \
-    mkdir -p $(TARGET_RAMDISK_OUT)/mnt \
-    mkdir -p $(TARGET_RAMDISK_OUT)/proc \
-    mkdir -p $(TARGET_RAMDISK_OUT)/sys \
+    $(TARGET_RAMDISK_OUT)/mnt \
+    $(TARGET_RAMDISK_OUT)/proc \
+    $(TARGET_RAMDISK_OUT)/sys \
 
 LOCAL_STATIC_LIBRARIES := \
     libfs_mgr \