msm: vidc: Add support for IDR flag in v4l2 and video driver

I-frame and IDR-frame for v4l2 clients was same, there was no way to
differentiate them. Adding separate flag for IDR helps clients
differentiate I from IDR.

CRs-fixed: 471371 473864
Change-Id: I4a945d9ad256bfb305a11aace91245f99e241798
Signed-off-by: Ashray Kulkarni <ashrayk@codeaurora.org>