interconnect: qcom: Support bcm-voter-specific TCS wait behavior

Currently, all bcm-voters follow the same logic for when a tcs_cmd needs
to wait for completion. This logic sets tcs_cmd::wait = true for the
last command in each TCS (AMC, WAKE, and SLEEP). However, this isn't
necessarily the desired behavior for each bcm-voter, so allow which
TCS's require wait-for-completion to be specified in devicetree.

Additionally, change the default behavior to only wait for completion in
AMC and WAKE sets. The SLEEP set generally does not require this, since
in essentially all cases resources are only being disabled in the sleep
set and that can happen asynchronously in parallel with the rest of the
power collapse sequence.

Change-Id: If782f88c2748f018863fe1cdbc8c82ad427c3e9f
Signed-off-by: Mike Tipton <mdtipton@codeaurora.org>