Revert back to SLUB
msm: vidc: free the recon buffers in cleanup function
- The recon buffers were not released when video recording
  was killed abruptly leading to memory leak.

- Fix provided to release the recon buffers when media
  server killed abruptly.

Change-Id: I48ac1a592719446b7e4bf87bbd707d09351d1e61
Signed-off-by: srikarri <sridur@codeaurora.org>