lt01-common: Use kernel exFAT filesystem

Faster than fuse exFAT, patched exFAT vold needed

Change-Id: I7e9da877e5218743385c890bc870f32dd4aea7f2
init.smdk4x12.rc: Fix ext4 and f2fs formatted SD card access

Change-Id: Ia960c79eace92f58499faea2f2fcdbf26486188e