msm: vidc: Remove 'I' frame handling as sync frame

Driver already has sync frame as separate flag. we don't
need to tag I frame as sync frame since this is causing
issues for AVC/HEVC codecs.

CRs-Fixed: 2298365
Change-Id: Ieaae5b4df332f959df9636f80d82ba66436fc066
Signed-off-by: Tapas Kumar Kundu <tkundu@codeaurora.org>