CHROMIUM: mwifiex: Send individual channel TLVs

CHROMIUM: mwifiex: Send individual channel TLVs

This is a workaround for possible buffering issues for scans
in environments where BSSes are plentiful.  This improves
reliability of scanning by breaking up the scan commands.

Signed-off-by: Paul Stewart <pstew@chromium.org>
BUG=chrome-os-partner:14655
TEST=Testbed runs.

Change-Id: If2f8a6558561efbf36998a8ebdf2ce9ebec3dcdd
Reviewed-on: https://gerrit.chromium.org/gerrit/35435
Reviewed-by: Ryan Cairns <rtc@chromium.org>
Commit-Ready: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>