From: Jonathan Lemon <redacted>
Date: Tue, 30 Jul 2019 07:40:31 -0700

The recent conversion of skb_frag_t to bio_vec did not include
skb_frag's page_offset.  Add accessor functions for this field,
utilize them, and remove the union, restoring the original structure.

v2:
  - rename accessors
  - follow kdoc conventions

Series applied, thanks Jonathan.