Revert "Android: sdcardfs: Don't do d_add for lower fs"

This reverts commit e92f7219.

This change caused issues for sdcardfs on top of vfat

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: Ife2ac6d9af40e4ddb95b7261e1dad4d7817e3779