net: wireless: bcmdhd: Gscan improvement changes

1. Has changes to support adaptive Legacy PNO + Gscan
2. Gscan bug fixes - Correctly set batch results flag, do not filter
out dfs channels (if present) for gscan + Legacy PNO
3. generic fixes: Clean up fw if cfg fails for PNO/Gscan

Will need compatible FW for gscan to work (ver: 7.35.79.38 or greater)

Change-Id: I91d7536181789d2bbce9e80846eae79acc12e5eb
Signed-off-by: Ashwin <ashwin.bhat@broadcom.com>