net: wireless: bcmdhd: Update to version 1.88.6

- Fix improper printing of negative value from dhd dump command
- Fix too long scan dwell time when connect command is coming
  with no channel info
- Remove unused WLBTAMP code

Change-Id: I4acdb3aa54ab79200299ac42d0d537c2beccc377
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>