Release all blocks after the pipe is disabled, even when vsync
didn't happen in some error cases. Allow requesting SMB multiple
times before configuring to hardware, by releasing blocks not
programmed to hardware yet for shrinking case.

This fixes a potential leak of shared memory pool blocks.
Signed-off-by: Wentao Xu <wentaox@codeaurora.org>
Tested-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>