msm: vidc: Cleanup of SVC header setting

Currently when multilayered encoding is enabled,
SVC header is automatically set by firmware hence
we don't need an external setting. Clean up code
related to the setting.

CRs-Fixed: 2012385
Change-Id: I00f3039326ff937389c5a8a03518c59b35b182bc
Signed-off-by: Vaibhav Deshu Venkatesh <vdeshuve@codeaurora.org>