init.rc: Create /storage mountpoint so Dalvik can mark as slave in zygotes

Mount a tmpfs as /storage in order to create a mountpoint, so that Dalvik
can later mark /storage as slave in zygotes.

Must mount in early-init as some devices' init.hardware.rc populate
/storage then, which the tmpfs would overwrite if mounted later.

Must use tmpfs as rootfs can't be bind mounted (otherwise "mount rootfs
/storage /storage bind" would work as an alternative).
Init: Allow building of init that is compatible with second init boot

When using second init init has already set up /dev /proc, etc
this will prevent duplicate mount points for those
Define BOARD_USE_NO_DEVFS_SETUP := true to use

Change-Id: I5620664b32e08f39da7ef7c7f9c3824d01f930d6
Signed-off-by: dhacker29 <davidhackerdvm@gmail.com>