slim_msm: Do not disconnect BAM pipe if ADSP HW goes down

BAM pipe HW resources (e.g. RX message queue) are in ADSP.
When ADSP HW is reset, these resources won't be clocked and won't be
accessible. sps_disconnect programs such HW resources.
Make sure the HW resources are not touched in event of ADSP HW reset

Change-Id: Id336cc258e2e3466e5a0be65cbff662f9d611c6e
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>