/ should not have any character/block devices, so might as well pass in
the nodev flag.
Bug: 73255020
Test: aosp_sailfish still boots
Test: sailfish:/ # find / -xdev -a \( -type b -o -type c -o -type p -o -type s \)
sailfish:/ #
Test: rootfs on / type rootfs (rw,seclabel)
/dev/root on / type ext4 (ro,seclabel,nodevrelatime)
Change-Id: Ia73e04b53a47506892d9d3cb61b471b81bb72dc3