net: wirelss: bcmdhd fixed pcie suspend/resume issue

Sometimes, system doesn't recover the config registers during resume
due to wakelock.  So, we need to save and restore the config registers in DHD

b/18220535 [WiFi] - Watchdog reset after PCIE link down and Event Hang

Signed-off-by: Ecco park <eccopark@broadcom.com>
Change-Id: Ib796b4833119a27bd79e3a667e40ee1e4d4878df