Fix for suspend/resume bug

Fix for suspend/resume bug

Currently, there are 2 callbacks registered with OS for getting notifications when system goes to suspend/resume.
Racing between these 2 callbacks is the reason for the failure.
With this fix, we avoid registering dhd callback for suspend/resume notification when cfg80211 is used. Relevent functionality in dhd suspend/resume callback function is moved to cfg80211 suspend/resume functions.

Change-Id: Ic29f711eed74d975e6d9558cf93899b85db0678d

BUG=chromium-os:13867, chromium-os:12337
TEST= Manually tested the suspend/resume functionality

[Olof Johansson, 2011-04-14 18:13:43]

Still need better patch subject and signed-off-by. But code comments below.

http://codereview.chromium.org/6851008/diff/1/drivers/staging/brcm80211/brcmf...
File drivers/staging/brcm80211/brcmfmac/dhd.h (right):

http://codereview.chromium.org/6851008/diff/1/drivers/staging/brcm80211/brcmf...
drivers/staging/brcm80211/brcmfmac/dhd.h:42: #endif
No need to ifdef the include.

http://codereview.chromium.org/6851008/diff/1/drivers/staging/brcm80211/brcmf...
drivers/staging/brcm80211/brcmfmac/dhd.h:131: extern volatile bool
dhd_mmc_suspend;
Extern volatile? Huge red flags. Please move to an appropriate header file, and
why is it volatile?

http://codereview.chromium.org/6851008/diff/1/drivers/staging/brcm80211/brcmf...
File drivers/staging/brcm80211/brcmfmac/wl_cfg80211.c (right):

http://codereview.chromium.org/6851008/diff/1/drivers/staging/brcm80211/brcmf...
drivers/staging/brcm80211/brcmfmac/wl_cfg80211.c:1973: #endif	/* 
defined(CONFIG_PM_SLEEP) */
If you move the variable out of ifdef, you can do away with the ifdefs here too
(same for the below).