/bin/wifi:  Save options per-interface rather than per-band.

This adds support for persisting options for interfaces with suffixes
(currently missing, due to an oversight).  It also simplifies the case
for dual-band radios; previously, there was code specifically to
handle the case in which options were persisted for both bands, and
the wrong ones got restored.

BUG=33755395

Change-Id: I5fdb70fad5295d163e372199ffecefd498aee2c2
4 files changed