msm: vidc: Fix encoder input extradata size calculation

Encoder input extradata size calculation uses get control
and this is called before control initialization in inst
init. Change this to take the control as a parameter and
pass 0 during init.

CRs-Fixed: 2368458
Change-Id: I8bd7c347d511d8468f4b01e0cf9f2665649063c8
Signed-off-by: Vaibhav Deshu Venkatesh <vdeshuve@codeaurora.org>