CEC: Add implementation of getVendorId method to default HdmiCec

Bug: 185434120
Test: manual
Change-Id: Ie6b1f0d2551ca271d492c59be5897f77e18b0698
diff --git a/tv/cec/1.0/default/HdmiCecDefault.cpp b/tv/cec/1.0/default/HdmiCecDefault.cpp
index c7fb31f..7b986de 100644
--- a/tv/cec/1.0/default/HdmiCecDefault.cpp
+++ b/tv/cec/1.0/default/HdmiCecDefault.cpp
@@ -117,7 +117,7 @@
 }
 
 Return<uint32_t> HdmiCecDefault::getVendorId() {
-    return 0;
+    return property_get_int32("ro.hdmi.vendor_id", 0x000c03 /* HDMI LLC vendor ID */);
 }
 
 Return<void> HdmiCecDefault::getPortInfo(getPortInfo_cb callback) {