Android framework indicates dhcp start and stop using power save
(ps disable for dhcp start, ps enable for dhcp stop).
Use this new indication method for any of the dhcp dependent operations.
Also remove resetting dhcp_done flag in csr_roam_connect() function,
as assumption of dhcp will trigger for every new connection is not
correct, like in static IP address case there won’t be dhcp indications,
and this flag remains false.
Change-Id: I3a995d859c39591b0a9fb4bc6e636e580c02dbd4
CRs-Fixed: 1088523
3316f402c3