Skip logical partitions in non-AVB2 case too

Follow up to the change made for AVB2 devices in
I19371b05912240480dc50864a2c04131258a7103.

The same consideration must be made in the fall through case, which
is taken either if AVB is completely disabled, or the dm-verity / AVB1
mechanism is used.

Bug: 113175337
Test: boot test on cuttlefish
Change-Id: I99d46a2c2630c40f5f5c02279b11e423998a1e05