msm: ADSPRPC: Do not release rpc session when interrupted

Release the RPC session only when the file handle is closed
and not release it when interrupted. It is possible for the
completion to be interrupted in power collapse scenarios
when the tasks are frozen.

Change-Id: Ib507c6ada624bb68c0e6aa798f0ca76c3213af65
Acked-by: Sathish Ambley <sambley@qti.qualcomm.com>
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>