msm: bam_dmux: ensure resources are released in UL timeout

Fix a race condition which required one or more bam_dmux clients to open
a channel within one second of bam_dmux receiving the remote open command
in order to properly release resource references when processing the
uplink activity timeout.  Not releasing the resources results in the
device being unable to enter suspend and buses to be unnecessarly clocked,
which causes additional power drain.

CRs-Fixed: 339235
Change-Id: Ieade0f103231838ebc3756a2ec9b2bc312cf7705
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>