SoftVPXEncoder: Disable lagged vp9 encoding

VP9 encoding on realtime should not have any lag set (it is set to
the library default right now for VBR mode). Unconditionally
disable it.

Test: CtsVideoTestCases

Bug: 62274213
Change-Id: Iab1abcae4f648198cb2b9bc634f73f612025f986
1 file changed