msm: bam_dmux: update SSR handling to reflect disconnect ack on by default

When subsystem restart of the modem is triggered, the SSR handling function
disables the disconnect ack feature.  Later, when the modem reboots, it
expects the disconnect ack feature to be enabled by default as it was when
the modem first booted.  This causes a problem when the modem times out
waiting for the disconnect ack and asserts.

Fix the issue by changing the SSR code in bam_dmux to reenable the
disconnect ack feature instead of disabling it.

CRs-Fixed: 377493
Change-Id: Ibd6ee7770c3ad57fabcf239b0175f2002ca45268
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>