vidc: 1080p: Handle flush for interlaced clips.

Video core expects one field per buffer for interlaced
clip playback.If a flush is issued we should reset the
need next field flag, so that new bitstream is processed
after flush is completed.
Reconfig flag shouldn't be reset in case of EOS.

Change-Id: Idf50a24c29e904a958b0b1e850813e2d9fc4346d
CRs-fixed: 382368
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>