net: wireless: bcmdhd: trying to fix common wifi disconnect on suspend bug

lowered DTIM skip to 2 in suspend mode. Needs testing.

The issue is described to affect the Galaxy Nexus, Nexus 4 and Nexus 7:
https://code.google.com/p/android/issues/detail?id=40792

Signed-off-by: Boy Petersen <boypetersen@gmail.com>