msm: cvp: Avoid releasing buffers during boot

CVP auto PIL opens CVP for early initialization. However session
buffers were not created in that case. Avoid releasing buffers
if session is created for auto PIL.

Change-Id: I3339f1b865b0e106af0bbed47ad067e2d183e5b5
Signed-off-by: George Shen <sqiao@codeaurora.org>