soc: qcom: bam_dmux: Add fast-shutdown flag

The UL_TIMOUT_DELAY of 1sec is very high in CDRX usecase where
the Modem and the network agree that no data will be exchanged for
a set amount of time. In this case A2 want to power collapse early
which is done by UL unvote from BAM DMUX.

Add a flag to reduce the UL_TIMEOUT_DELAY for early UL unvote from
BAM DMUX to allow A2 early power collapse.

CRs-Fixed: 826107
Change-Id: Iea99d59f0eadf2f385c66e3280a194be38c6d003
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>