C2SoftVpxEnc: process QP bounding parameters

The software VPx encoder now parses the QP bounds passed by the
codec2 framework and uses those values in the codec's configuration.

Bug: 182015210

Test: MediaCodec based application to set QP bounds and review the encoded clip's QP values
Change-Id: I3c42cfab33fe4b500d5edc93c07ec5d295d18c4b
2 files changed