msm: vidc: Set mode1 for VP8 always

VP8 encoder should always be set as work mode1.
Mode2 is not compatible for 4096 resolution.

CRs-Fixed: 2315963
Change-Id: I8175448387c0dd98ce3a778f584788fc2a459ed2
Signed-off-by: Vaibhav Deshu Venkatesh <vdeshuve@codeaurora.org>