Customize Bluetooth sniff interval

Fix an earlier commit that prevents from customizing some of
the Bluetooth sniff parameters - those cannot be overwritten
anymore in the bdroid_buildcfg.h file.

Also, fixed the indexing in tables bta_dm_pm_cfg[]
and bta_dm_pm_spec[]

Bug: 22676670
Change-Id: I3a7074b9a9c91d312dc5d4314b7c304baf4ae20d