Revert "msm: vidc: Memset and flush codec context buffers"

This revert fixes a vdec bug. A hw timeout happens when decoding
video (can't play any video):

<3>[  231.779459,0] vidc_timer_fn() Timer expired
<7>[  231.779642,0] Queue the work for timer
<3>[  231.779764,0] vidc_timer_handler() Timer expired
<4>[  231.779856,0] vcd_hw_timeout_handler:
<6>[  231.780039,0]     * vcd_hw_timeout_cmn:
<7>[  231.780253,0] vidc_timer_stop(): stop timer
<3>[  231.781504,0] NOT_REPRODUCED: flush original frame = 0, c8f7c0a0
<4>[  231.829757,0] HW Reset done

This reverts commit 77a4e0a77ae4f03796c9cce1f647ba429ec598e5.

Change-Id: Id3ef4907d27f423411fa2718f1098fdb0435026b