Revert "mm-video-v4l2: Protect buffer access and increase input buffer size"

This reverts commit 4f368aba.

Reason for revert: regressions at oc-mr1/bullhead and pi/walleye

Change-Id: Ie9caad90482698913db06cdb9aeebfd869fe1a6a
Bug: 64340487
Bug: 78291359
Bug: 78913375