msm: vidc: Update extradata plane size during valid extradata index

Even when extradata is not enabled for video port, driver is updating
size of plane at extradata index. Doing so, it overwrites the size
of data plane with extradata plane.
Keep a check to update the extradata plane size only when extradata
is enabled on that port.

CRs-Fixed: 2083553
Change-Id: I221a9d4f77b5c521567d09e077ac6174d2058bd4
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>