msm: bam_dmux: trigger modem subsystem restart in case of timeout

If bam_dmux times out waiting for a power collapse protocol response from
the modem, bam_dmux assumes the modem has crashed and will disable itself
until the subsystem restart callback is triggered.

Change the behavior in bam_dmux to request that the modem subsystem
restarts regardless of its current state so that the restart callback is
always triggered.

CRs-Fixed: 495690
Change-Id: I076ab16dd727694feb68b9e9052b1b6a60a2b0ca
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>