HDMI: If active source was set, ignore <Standby> from non active source

In CTS for TVs we can't mock active source so we can't pass 11.1.3-2 and
11.1.3-3 if we ignore all <Standby> messages. We are ignoring this
message only if a connected devices asserted active source after TV woke
up.

Flag: EXEMPT bugfix
Bug: 344490157
Bug: 323793251
Test: atest HdmiCecLocalDeviceTvTest
Change-Id: Iecbe9410f87ac86ce84a1f9f9e36e9ebbf82ec78